Optical resin composition, optical resin material using the same, optical

ABSTRACT

The invention provides an optical resin composition being transparent, having suitable adhesion and necessary impact absorption for protection of an image display device etc., not affecting constituent materials of a image display panel, and being excellent in reliability, and an optical resin material using the same. 
     Disclosed is an optical resin composition containing (A) a first acrylate derivative that is a compound having one polymerizable unsaturated bond in its molecule, (B) a second acrylate derivative that is a compound having two or more polymerizable unsaturated bonds in its molecule, and (C) an acrylate derivative polymer, and an optical resin material produced by curing reaction of the optical resin composition.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. application Ser.No. 12/438,448, filed Feb. 23, 2009. This application is related toapplication Ser. No. 13/355,600 filed Jan. 23, 2012, which is adivisional of application Ser. No. 12/438,448, filed Feb. 23, 2009, thecontents of all of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an optical resin composition and anoptical resin material, which are useful in inhibiting breakage of animage display panel or in absorbing stress and impact and are excellentin transparency.

The present invention also relates to an optical filter for imagedisplay device and an image display device, which have an optical resincomposition or an optical resin material which is useful in inhibitingbreakage of an image display device or in absorbing stress and impactand is excellent in transparency.

BACKGROUND ART

A representative image display panel is exemplified by liquid crystaldisplay (LCD). The liquid crystal display is a thin and easily damageddisplay component consisting of transparent electrodes, a liquid crystalcell having a liquid crystal charged and sealed via a gap of few micronsbetween glass substrates of about 1 mm in thickness with a pixel patternetc. formed thereon, and an optical film or the like (for example, apolarization plate) stuck to both external sides of the cell.Particularly for use in cell phones, game machines, digital cameras, andin-car products, therefore, a liquid crystal display having a structurewherein a transparent front plate (protective panel) is arranged with apredetermined space in front of the liquid crystal display is generallyused.

Large liquid crystal displays prevailing at present are those whereinthe surface of a front polarization plate for liquid crystal panel hasbeen subjected to antiglare (AG) treatment for reflection reduction. Inthe case of this structure, no measure is taken for impact absorption,and impact resistance is given by a structure of the whole of a paneland a set. The problem of this structure is that an image seems blurredby AG treatment, the panel is warped upon touching the surface, todisorder an image, stains are hardly removed due to AG treatment, andupon strong rubbing, flaws are easily caused, and also that as the sizeof a panel will be increasing in future, the impact resistance of thepanel would be reduced to be problematic in impact resistance.

Accordingly, it is conceivable that a front plate subjected toantireflection (AR) treatment is placed in front of a liquid crystalpanel, to overcome disadvantages originating from AG treatment. In thiscase, however, a reduction in transmittance and a deterioration in imagequality due to ghost image would be caused when air exists the spacebetween the front plate and the liquid crystal panel, so filling thespace with a resin etc. has been proposed (Patent Documents 1, 2, 3 and4).

It is determined under UL standards, the Radio Wave Control Act, etc.that a cathode ray tube (CRT) made of glass, when used in an imagedisplay device (display) (including a television), be free of scatteringor not liable to penetration in an impact resistance test with adropping steel ball.

Accordingly, to implement this standard, the glass of CRT should bedesigned to be thick, which results in an increase in the weight of CRT.As a means of conferring antiscattering property without increasing thethickness of the glass, a method of laminating a self-restoring,synthetic resin protective film on the glass has been proposed (seePatent Documents 5 and 6). This proposal is characterized byantiscattering property, but does not meet prevention of glass breakage.

On the other hand, PDP that is one kind of flat panel display (FPD) isprovided via an about 1 to 5 mm space with a front plate (e.g., glass)of about 3 mm in thickness in front (viewable side) of PDP in order toprevent breakage. Accordingly, the area of the front plate increaseswith an increasing size of PDP, thus increasing the weight of PDP.

Accordingly, it has been proposed for prevention of breakage of an imagedisplay device (display) that a specific resin is laminated on thesurface of the display, or an optical filter having a specific resinlaminated thereon is laminated on the surface of the display (see PatentDocuments 7, 8 and 9).

-   Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No.    05-011239-   Patent Document 2: Japanese Patent Application Laid-Open (JP-A) No.    03-204616-   Patent Document 3: Japanese Patent Application Laid-Open (JP-A) No.    06-59253-   Patent Document 4: Japanese Patent Application Laid-Open (JP-A) No.    2004-125868-   Patent Document 5: Japanese Patent Application Laid-Open (JP-A) No.    06-333515-   Patent Document 6: Japanese Patent Application Laid-Open (JP-A) No.    06-333517-   Patent Document 7: Japanese Patent Application Laid-Open (JP-A) No.    2004-58376-   Patent Document 8: Japanese Patent Application Laid-Open (JP-A) No.    2005-107199-   Patent Document 9: Japanese Patent Application Laid-Open (JP-A) No.    2004-263084

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

However, oil used in Patent Document 1 is hardly sealed for preventingleakage and may affect materials used in a liquid crystal panel, andwhen a front plate is cracked, there arises a problem of oil leakage.Unsaturated polyester in Patent Document 2 is easily yellowed and itsapplication to the display is not desirable. Silicone in Patent Document3 is poor in adhesiveness and thus requires an additionalpressure-sensitive adhesive for fixation, to make the processcomplicated, and does not have strong adhesiveness to thepressure-sensitive adhesive and is thus released upon application of animpact, to cause a problem of inclusion of bubbles. A polymer of acrylicmonomers in Patent Document 4, although not requiring an additionalpressure-sensitive adhesive when used in small instruments, is stillpoor in adhesiveness and requires an additional pressure-sensitiveadhesive when used in supporting a front plate of a large display, thusmaking the process complicated. The starting material is composedexclusively of monomers and thus has low viscosity and high curingshrinkage, to cause a problem of difficult formation of a large areauniform film.

In Patent Documents 7 and 8, there is no particular consideration givento a composition of resin materials used, and a means for exhibitingadhesiveness or transparency is ambiguous. Particularly in PatentDocument 7, there is no consideration given to humidity resistancereliability of resin, and when resin materials in a compositionspecifically shown in the Examples are used, the resin after applicationto a display becomes clouded in a humidity resistance test in a shorttime. In Patent Document 8, acrylic acid is used as a part of resinspecifically shown in the Examples, and the resin becomes clouded in ahumidity resistance test in a long time and causes a problem ofcorroding a metal with which the resin is contacted in the humidityresistance test. Examination in Patent Documents 7 and 8 is consideredinsufficient from the viewpoint of attaining more excellent impactabsorption. In Patent Document 8, the thickness of an impact-resistantlayer using resin is defined in the range of 0.2 to 1 mm, which ishowever not a disclosure from the viewpoint of improving impactabsorption by increasing the thickness. In Patent Document 9, there isconsideration given to resistance to humidity and heat, but given aresin starting material composition described in this patent document,it is not possible to expect significant improvement in impactresistance. The thickness of a resin layer in the Examples is 1 mm, andfrom the viewpoint of attaining more excellent impact absorption,examination is considered insufficient. When a resin relatively softafter curing, as described in the Examples in Patent Document 9, is usedthickly, it is considered that the surface hardness of the resultingfront filter is reduced to cause a problem in abrasion resistance.

Accordingly, a first object of the present invention is to provide anoptical resin composition being transparent, having suitable adhesionand necessary impact absorption for protection of an image displaydevice etc., and not affecting constituent materials of a image displaypanel etc., and an optical resin material using the same.

A second object of the present invention is to provide an optical resincomposition excellent in reliability in moisture resistance, and anoptical resin material using the same.

A third object of the present invention is to provide an optical filterfor an image display device having an optical resin composition beingtransparent, having suitable adhesion and necessary impact absorptionfor protection of an image display device, not affecting constituentmaterials of a image display panel, and being excellent in reliabilityin moisture resistance, and an optical resin material using the same.

A fourth object of the present invention is to provide an image displaydevice having impact resistance and attaining a vivid image of highcontrast without ghost image.

Means for Solving the Problems

The means for solving the problems is as follows.

(1) An optical resin composition containing (A) a first acrylatederivative that is a compound having one polymerizable unsaturated bondin its molecule, (B) a second acrylate derivative that is a compoundhaving two or more polymerizable unsaturated bonds in its molecule, and(C) an acrylate derivative polymer.

(2) The optical resin composition according to the above-mentioned (1),wherein (B) the second acrylate derivative is a high-molecular-weightcrosslinking agent.

(3) The optical resin composition according to the above-mentioned (1)or (2), wherein the compounding amounts of the respective componentsbased on 100 parts by weight of (A) the first acrylate derivative, (B)the second acrylate derivative and (C) the acrylate derivative polymerin total are (A) 14 to 89.49 parts by weight, (B) 0.1 to 50 parts byweight, and (C) 10 to 80 parts by weight.

(4) The optical resin composition according to the above-mentioned (1),wherein:

(A) the first acrylate derivative consists of a mixture of an alkylacrylate having an alkyl group containing 4 to 18 carbons (referred tohereinafter as AA monomer) and a hydroxyl-containing acrylaterepresented by the following general formula (I) (referred tohereinafter as HA monomer):CH₂═CHCOO(C_(m)H_(2m)O)_(n)H  General Formula (I)wherein m is 2, 3 or 4, and n is an integer of 1 to 10,

(C) the acrylate derivative polymer is a copolymer obtained bypolymerizing AA monomer with HA monomer, and

the HA monomer is incorporated such that the proportion (M % by mass) ofHA monomer in (A) the first acrylate derivative and the proportion (P %by mass) of HA monomer in (C) the acrylate derivative polymer satisfythe following relationship:−8≦(P−M)≦8  Formula (I)

(5) The optical resin composition according to the above-mentioned (4),wherein (A) the first acrylate derivative is a mixture produced bymixing AA monomer at a proportion of 50 to 87% by weight with HA monomerat 13 to 50% by weight, and (C) the acrylate derivative polymer is acopolymer produced by polymerizing AA monomer at a proportion of 50 to87% by weight with HA monomer at 13 to 50% by weight.

(6) The optical resin composition according to the above-mentioned (4)or (5), wherein the compounding amounts of the respective componentsbased on 100 parts by weight of (A) the first acrylate derivative, (B)the second acrylate derivative and (C) the acrylate derivative polymerin total are (A) 36 to 84.49 parts by weight, (B) 0.5 to 50 parts byweight and (C) 15 to 60 parts by weight.

(7) The optical resin composition according to any of theabove-mentioned (1), (2), (4) or (5) which further contains (D) apolymerization initiator.

(8) The optical resin composition according to the above-mentioned (7),wherein the compounding amount of (D) the polymerization initiator basedon 100 parts by weight of (A) the first acrylate derivative, (B) thesecond acrylate derivative, (C) the acrylate derivative polymer and (D)the polymerization initiator in total is 0.01 to 5 parts by weight.

(9) The optical resin composition according to the above-mentioned (7),wherein (D1) a photopolymerization initiator is contained as (D) thepolymerization initiator.

(10) The optical resin composition according to the above-mentioned (9),wherein the compounding amount of (D1) the photopolymerization initiatorbased on 100 parts by weight of (A) the first acrylate derivative, (B)the second acrylate derivative, (C) the acrylate derivative polymer and(D1) the photopolymerization initiator in total is 0.1 to 5 parts byweight.

(11) The optical resin composition according to the above-mentioned (9),wherein (D1) the photopolymerization initiator is at least one memberselected from the group consisting of an α-hydroxyalkyl phenonecompound, an acylphosphine oxide compound,oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl) phenyl)propanone, and amixture of oxy-phenyl-acetic acid2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic acid2-[2-hydroxy-ethoxy]-ethyl ester.

(12) The optical resin composition according to any of theabove-mentioned (4) or (5), wherein the AA monomer is 2-ethylhexylacrylate, isooctyl acrylate and/or n-octyl acrylate, and the HA monomeris at least one member selected from the group consisting of2-hydroxyethyl acrylate, 1-hydroxyethyl acrylate, 2-hydroxypropylacrylate, 3-hydroxypropyl acrylate, 1-hydroxypropyl acrylate,4-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, 2-hydroxybutylacrylate, and 1-hydroxybutyl acrylate.

(13) The optical resin composition according to any of theabove-mentioned (1), (2), (4) or (5) wherein the weight-averagemolecular weight of (C) the acrylate derivative polymer is 100,000 to700,000.

(14) The optical resin composition according to any of theabove-mentioned (9), wherein the compounding amounts of the respectivecomponents based on 100 parts by weight of (A) the first acrylatederivative, (B) the second acrylate derivative, (C) the acrylatederivative polymer and the (D1) photopolymerization initiator in totalare (A) 15 to 40 parts by weight, (B) 5 to 40 parts by weight, (C) 39 to59 parts by weight and (D1) 0.5 to 2.0 parts by weight.

(15) The optical resin composition according to any of theabove-mentioned (2), wherein the high-molecular-weight crosslinkingagent includes a alkylene glycol containing 1 to 4 carbons as a part ofits starting material and has a weight-average molecular weight of 4,000to 20,000.

(16) An optical resin material produced by curing reaction of theoptical resin composition according to any of the above-mentioned (1)(2), (4) or (5).

(17) The optical resin material according to the above-mentioned (16),which is sheet-shaped or film-shaped.

(18) An optical filter for image display device, which has a layerconsisting of an optical resin material produced by curing the opticalresin composition according to any of the above-mentioned (1) (2), (4)or (5).

(19) An image display device having, in a viewable side, a layerconsisting of an optical resin material produced by curing the opticalresin composition according to any of the above-mentioned (1), (2), (4)or (5).

(20) An image display device having a layer consisting of an opticalresin material produced by curing the optical resin compositionaccording to any of the above-mentioned (1), (2), (4) or (5) between animage display panel and a front panel or a transparent protectivesubstrate.

Effect of the Invention

The optical resin composition of the present invention after curingreaction has excellent impact absorption and is excellent intransparency.

The optical resin composition of the present invention, because of asimilar composition between polymers and monomers therein, can increasethe solubility of the polymers, can prepare a transparent resincomposition or cured product even when a high-molecular-weight polymeris used, and is excellent in reliability in humidity resistance. Theoptical resin composition has been diluted with monomers and can thus beformed in the absence of a solvent to prepare a bubble-free thick filmor sheet.

The optical resin composition of the present invention contains ahigh-molecular-weight polymer at a relatively high concentration, and isthus excellent in impact absorption even when formed into a film of thinthickness. Accordingly, the resulting film has hardness to enableprevention abrasion resistance from decreasing. Due to this hardness,the film is hardly plastically deformed and can exhibit more excellentimpact absorption with thicker film thickness. The film has strongcohesion and flexibility and is thus free of cracking and lining uponbending or winding on a roll.

By using a high-molecular-weight crosslinking agent, the composition canprevent adhesion from varying due to an error in compounding, so a filmor sheet excellent in characteristic stability can be manufactured. Theoptical resin composition of the present invention does not affectmaterials generally used in image display devices such as liquid crystaldisplay and PDP.

The optical resin material of the present invention can be obtained bycuring reaction of the optical resin composition of the presentinvention, and can be easily shaped into a sheet. This optical resinmaterial has been endowed with adhesiveness and can thus be stuck to asubstrate such as glass and the like without using a pressure-sensitiveadhesive or an adhesive.

An optical filter for an image display device and an image displaydevice, such as liquid crystal display provided with a transparent resinlayer obtained by using the optical resin composition or the opticalresin material succeed to the working effect of the optical resincomposition and the optical resin material.

The optical resin composition and the optical resin material of thepresent invention are used suitably as those forming a transparent resinlayer in front of an image display panel.

According to the present invention, there can be provided an opticalfilter for an image display device, which is transparent, has impactabsorption, and is excellent in reliability in humidity resistance.

According to the present invention, there can also be provided an imagedisplay device which has impact resistance and gives a vivid image ofhigh contrast without ghost image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view showing a liquid crystaldisplay using the optical resin material of the present invention;

FIG. 2 is a schematic cross-sectional view showing another example of aliquid crystal display using the optical resin material of the presentinvention;

FIG. 3 is a schematic cross-sectional view showing another example of aliquid crystal display using the optical resin material of the presentinvention;

FIG. 4 is a schematic cross-sectional view showing another example of aliquid crystal display using the optical resin material of the presentinvention;

FIG. 5 is a schematic cross-sectional view showing a conventional liquidcrystal display; and

FIG. 6 is a schematic cross-sectional view showing another example ofthe conventional liquid crystal display.

DESCRIPTION OF NUMERALS

-   1 Liquid crystal display cell-   2 Polarization plate-   3 Gap (air layer)-   3′ Optical resin material-   4 Backlight system-   5 Transparent protective substrate

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the optical resin composition, the optical resin material,the optical filter and the image display device according to the presentinvention are described.

In this specification, “acrylic acid” as in acrylate derivative shallinclude “methacrylic acid”.

<Optical Resin Composition>

The optical resin composition of the present invention is an opticalresin composition containing (A) a first acrylate derivative that is acompound having one polymerizable unsaturated bond in its molecule, (B)a second acrylate derivative that is a compound having two or morepolymerizable unsaturated bonds in its molecule, and (C) an acrylatederivative polymer. Hereinafter, the components contained in the opticalresin composition of the present invention are described respectively.

[(A) First Acrylate Derivative]

In the present invention, (A) the first acrylate derivative includes anacrylate or methacrylate having one polymerizable unsaturated bond inits molecule, and derivative thereof etc. Specific examples of thecompound having one polymerizable unsaturated bond in its moleculeinclude alkyl methacrylates such as methyl methacrylate, n-butylmethacrylate, i-butyl methacrylate, 2-ethylhexyl methacrylate, isonoylmethacrylate, n-octyl methacrylate, lauryl methacrylate, and stearylmethacrylate, alkyl acrylates such as methyl acrylate, n-butyl acrylate,i-butyl acrylate, 2-ethylhexyl acrylate, isonoyl acrylate, and n-octylacrylate, aralkyl methacrylates such as benzyl methacrylate, aralkylacrylates such as benzyl acrylate, alkoxyalkyl methacrylates such asbutoxyethyl methacrylate, alkoxyalkyl acrylates such as butoxyethylacrylate, aminoalkyl methacrylates such as N,N-dimethylaminoethylmethacrylate, aminoalkyl acrylates such as N,N-dimethylaminoethylacrylate, polyalkylene glycol alkyl ether acrylate such as diethyleneglycol ethyl ether methacrylate, triethylene glycol butyl ethermethacrylate, and dipropylene glycol methyl ether methacrylate,polyalkylene glycol alkyl ether methacrylates such as diethylene glycolethyl ether acrylate, triethylene glycol butyl ether acrylate, anddipropylene glycol methyl ether acrylate, polyalkylene glycol aryl ethermethacrylates such as hexaethylene glycol phenyl ether methacrylate,polyalkylene glycol aryl ether acrylates such as hexaethylene glycolphenyl ether acrylate, alicyclic group-containing methacrylates oracrylates such as cyclohexyl methacrylate, cyclohexyl acrylate,dicyclopetanyl methacrylate, dicyclopentanyl acrylate, isobornylmethacrylate, methoxylated cyclodecatriene methacrylate, isobornylacrylate, and methoxylated cyclodecatriene acrylate, fluorinated alkylmethacrylates such as heptadecaflorodecyl methacrylate, fluorinatedalkyl acrylates such as heptadecaflorodecyl acrylate,hydroxyl-containing methacrylates or acrylates such as 2-hydroxyethylmethacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate,2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutylacrylate, glycerol methacrylate, and glycerol acrylate,carboxyl-containing methacrylate or acrylate such as acrylate andmethacrylate, glycidyl-containing methacrylates or acrylates such asglycidyl methacrylate and glycidyl acrylate, and acrylamide.

These compounds having one polymerizable unsaturated bond in itsmolecule may be used alone or as a mixture of two or more thereof.

[(B) Second Acrylate Derivative]

In the present invention, (B) the second acrylate derivative includes anacrylate or methacrylate having two or more polymerizable unsaturatedbonds in its molecule, or derivatives thereof, and is particularlypreferably a compound having two or more acryloyl groups in itsmolecule. The second acrylate derivatives, when classified depending onmolecular weight, include (1) those having low-molecular weight of lessthan 1000, (2) those having middle-molecular weight of 1000 to 4000, and(3) those having high-molecular weight of 4000 or more, which will bedescribed respectively.

Among (1) the second acrylate derivatives, those having low-molecularweight include acrylate monomers such as bisphenol A diacrylate,1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanedioldiacrylate, 1,3-butylene glycol diacrylate, diethylene glycoldiacrylate, tripropylene glycol diacrylate, glycerol diacrylate,neopentyl glycol diacrylate, polyethylene glycol diacrylate,polypropylene glycol diacrylate, polybutylene glycol diacrylate,trimethylol propane triacrylate, pentaerythritol triacrylate,tris(acryloxyethyl)isocyanurate, pentaerythritol tetraacrylate,dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, anddipentaerythritol pentaacrylate, and acryl oligomers such as epoxyacrylate, polyester acrylate, urethane acrylate and acryl acrylate,among which diacrylates such as 1,6-hexanediol diacrylate,1,9-nonanediol diacrylate, tripropylene glycol diacrylate, polyethyleneglycol diacrylate, and polypropylene glycol diacrylate are preferable.From the above-described compounds having two or more polymerizableunsaturated bonds in its molecule, those having two or more acryloylgroups in its molecule can also be suitably selected and used.

Among (2) the second acrylate derivatives, those having middle-molecularweight include:

diacrylate compounds of an alkylene oxide adduct of bisphenol A (orthose compounds having their acryloyl groups replaced by methacryloylgroups) represented by the following general formula (a):

wherein R represents an ethylene group or a propylene group, and m and nindependently represents an integer of 1 to 20,

esterified compounds to which an epichlorohydrin modified product ofbisphenol A, and acrylic acid, were added (or those compounds havingtheir acryloyl groups replaced by methacryloyl groups) represented bythe following general formula (b):

wherein m and n independently represent an integer of 1 to 10,

diacrylate compounds of an alkylene oxide adduct of phosphoric acid (orthose compounds having their acryloyl groups replaced by methacryloylgroups) represented by the following general formula (c):

wherein R represents an ethylene group or a propylene group, and m and nindependently represents an integer of 1 to 20,

esterified compounds to which an epichlorohydrin modified product ofphthalic acid, and acrylic acid, were added (or those compounds havingtheir acryloyl groups replaced by methacryloyl groups) represented bythe general formula (d):

wherein m and n independently represent an integer of 1 to 10,

esterified compounds (having two acryl groups in one molecule) to whichan epichlorohydrin modified product of 1,6-hexanediol, and acrylic acid,were added (or those compounds having their acryloyl groups replaced bymethacryloyl groups) represented by the following general formula (e):

wherein m and n independently represent an integer of 1 to 20,

triacrylate compounds of an alkylene oxide adduct of phosphoric acid (orthose compounds having their acryloyl groups replaced by methacryloylgroups) represented by the following general formula (f):

wherein R represents an ethylene group or a propylene group, and threem's independently represent an integer of 1 to 20, and

triacrylate compounds of an alkylene oxide adduct of trimethylol propane(or those compounds having their acryloyl groups replaced bymethacryloyl groups) represented by the following general formula (g):

wherein R represents an ethylene group or a propylene group, and m, m′and m″ independently represent an integer of 1 to 20. These monomers canbe used alone or as a combination of two or more thereof.

Among (3) the second acrylate derivatives, those having high-molecularweight include a high-molecular-weight compound having two or morereactive unsaturated bonds (referred to in this specification as“high-molecular-weight crosslinking agent”) and are preferably thosehaving a weight-average molecular weight of 4,000 to 20,000, still morepreferably 8,000 to 16,000. When the molecular weight of thehigh-molecular-weight crosslinking agent is less than 4,000, a curedproduct is made easily brittle, while when the molecular weight ishigher than 20,000, the viscosity of the composition becomes too high,thus making formation of a sheet difficult. From the viewpoint ofcompatibility, the high-molecular-weight crosslinking agent ispreferably one using alkylene glycol containing 1 to 4 carbons as a partof its starting material.

The high-molecular-weight crosslinking agent includes:

(a) Dialcohol compound di(meth)acrylates which are obtained for exampleby reacting acrylic acid or methacrylic acid with a polyalkylene glycolsuch as polyethylene glycol, polypropylene glycol and polybutyleneglycol.

(b) Epoxy resin di(meth)acrylates which are obtained for example byreacting acrylic acid or methacrylic acid with an epoxy resin having twoepoxy groups in its molecule, such as diglycidyl ether of polyalkyleneglycol such as polyethylene glycol, polypropylene glycol andpolybutylene glycol.

(c) Di(meth)acrylates of polyesters having hydroxy groups at bothterminals, which are produced specifically by reacting polyester polyolswith saturated acid and polyhydric alcohol. The saturated acid includesaliphatic dicarboxylic acids such as azelaic acid, adipic acid andsebacic acid, and the polyhydric alcohol includes such as ethyleneglycol, propylene glycol, diethylene glycol, dipropylene glycol,butylene glycol, polyethylene glycol and polypropylene glycol. Thedi(meth)acrylates of polyesters can be obtained by reacting suchpolyester polyols with acrylic acid or methacrylic acid.

(d) Polyurethane di(meth)acrylates; specifically polyurethane isobtained by reacting a polyhydric alcohol compound with a polyhydricisocyanate compound. The polyhydric alcohol includes such as propyleneglycol, tetramethylene glycol, 1,4-butane diol, 1,5-pentane diol,1,6-hexane diol, neopentyl glycol, 1,4-cyclohexane dimethanol,2-methyl-1,8-octane diol, 1,9-nonane diol, 3-methyl-1,5-pentane diol,poly-1,2-butylene glycol, polypropylene glycol, polytetramethyleneglycol, an ethylene glycol-propylene glycol/block copolymer, an ethyleneglycol-tetramethylene glycol copolymer, methyl pentane diol-modifiedpolytetramethylene glycol, propylene glycol-modified polytetramethyleneglycol, a propylene oxide adduct of bisphenol A, a propylene oxideadduct of hydrogenated bisphenol A, a propylene oxide adduct ofbisphenol F, and a propylene oxide adduct of hydrogenated bisphenol F.The polyhydric isocyanate compound includes diisocyanates such astolylene diisocyanate, xylylene diisocyanate, diphenyl methanediisocyanate, hexamethylene diisocyanate, trimethyl hexamethylenediisocyanate, tetramethyl xylylene diisocyanate, isophoronediisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylenediisocyanate, hydrogenated diphenyl methane diisocyanate and norbornenediisocyanate, and polymers of the above diisocyanates or urea-modifiedor burette-modified diisocyanates. These polyhydric alcohols andpolyhydric isocyanates may be used alone or as a combination of two ormore thereof.

The polyurethane di(meth)acrylate can be obtained by reacting acrylicacid or methacrylic acid with such polyurethane that is a compoundhaving a hydroxyl group at a terminal obtained by reacting with anexcess of polyhydric alcohol.

(e) Compounds obtained by reacting polyurethane with a compound having ahydroxyl group and a reactive double bond; specifically the polyhydricalcohol and the polyhydric isocyanate compound as the polyurethanestarting materials are the same as described above.

Such polyurethane that is a compound having an isocyanate group at aterminal obtained by reacting with an excess of polyhydric isocyanatecan be reacted with a compound having a hydroxyl group and a reactivedouble bond, to form reactive double bond-terminated polyurethane.

The compound having a hydroxyl group and a reactive double bond includeacrylate derivatives such as 2-hydroxyethyl acrylate, 2-hydroxypropylacrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate,polyethylene glycol monoacrylate, polypropylene glycol monoacrylate,ethylene glycol-propylene glycol/block copolymer monoacrylate, ethyleneglycol-tetramethylene glycol copolymer monoacrylate,caprolactone-modified monoacrylate (trade name: Plaqucell FA series,manufactured by DAICEL CHEMICAL INDUSTRIES, LTD.) and pentaerythritoltriacrylate, and methacrylate derivatives such as 2-hydroxyethylmethacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropylmethacrylate, 4-hydroxybutyl methacrylate, polyethylene glycolmonomethacrylate, polypropylene glycol monomethacrylate, ethyleneglycol-propylene glycol/block copolymer monomethacrylate, ethyleneglycol-tetramethylene glycol copolymer monomethacrylate,caprolactone-modified monomethacrylate (trade name: Plaqucell FM series,manufactured by DAICEL CHEMICAL INDUSTRIES, LTD.) and pentaerythritoltrimethacrylate. These compounds are used alone or as a mixture of twoor more thereof.

From the toughness of a cured product, the high-molecular-weightcrosslinking agent is preferably polyurethane di(meth)acrylate andreactive double bond-terminated polyurethane (particularly one havingreactive double bonds based on acryloyl groups). Among them, thehigh-molecular-weight crosslinking agent is used preferably polyurethanewhose diol component consists of polypropylene glycol orpolytetramethylene glycol, more preferably one whose diol component ispolypropylene glycol or polytetramethylene glycol and whose diisocyanatecomponent is isophorone diisocyanate.

When (C) the acrylate derivative polymer described later is poor incompatibility with the high-molecular-weight crosslinking agent, thecured product becomes clouded if the amount of the high-molecular-weightcrosslinking agent is increased. By using an alkylene glycol in thestarting material of the high-molecular-weight crosslinking agent, thecompatibility with the polymer can be improved and the transparency canbe maintained regardless of the amount of the high-molecular-weightcrosslinking agent. By using the high-molecular-weight crosslinkingagent, the cured product can be prevented from becoming brittle orlowering adhesion to a considerable degree even if thehigh-molecular-weight crosslinking agent is used in a relatively largeamount. Accordingly, the amount of the crosslinking agent used can beincreased, and characteristics of the cured product can be preventedfrom changing due to an error in compounding.

The method of synthesizing the high-molecular-weight crosslinking agentmay be any of known polymerization methods such as bulk polymerization,solution polymerization, suspension polymerization and emulsionpolymerization can be used. These methods can also be applied tosynthesis of (C) the acrylate derivative polymer described later.

The high-molecular-weight crosslinking agents described above can beused alone or as a mixture of two or more thereof. Thehigh-molecular-weight compound, that is, the high-molecular-weightcrosslinking agent, is preferably used as (B) the second acrylatederivative.

[(C) Acrylate Derivative Polymer]

(C) The acrylate derivative polymer according to the present inventionis obtained by polymerization of a compound having one polymerizableunsaturated bond in its molecule (component (A)) among acrylatederivatives, or may be obtained by copolymerizing it with a compoundhaving two or more polymerizable unsaturated bonds in its molecule(component (B)) in such a range that the effect of the present inventionis not hindered.

The weight-average molecular weight (determined by using a calibrationcurve of standard polystyrenes by gel permeation chromatography; thisapplies hereinafter) is preferably 100,000 to 700,000, more preferably150,000 to 400,000, still more preferably 200,000 to 350,000.

(C) The acrylate derivative polymer may be a polymer obtained bypolymerizing one or more compounds having one polymerizable unsaturatedbond in its molecule or may be obtained by polymerizing them withpolymerizable compounds other than acrylate derivatives.

The polymerizable compounds other than acrylate derivatives may becompounds having one polymerizable unsaturated bond in its molecule,such as acrylonitrile, styrene, vinyl acetate, ethylene and propylene,besides (A) the first acrylate derivative can be used. The polymerizablecompounds other than acrylate derivatives may be compounds having two ormore polymerizable unsaturated bonds in its molecule (divinyl benzene orthe like) other than the second acrylate derivative can be used.

In the formulation of the optical resin composition of the presentinvention, (A) the first acrylate derivative can be used in regulatingthe viscosity of the composition. (B) The second acrylate derivative isused preferably in retaining the shape of a cured product of thecomposition.

(C) The acrylate derivative polymer is used preferably in improvingmechanical characteristics. By using (C) the acrylate derivativepolymer, curing shrinkage can be suppressed.

The preferable amounts of the respective components in the optical resincomposition of the present invention, based on 100 parts by weight of(A) the first acrylate derivative, (B) the second acrylate derivativeand (C) the acrylate derivative polymer in total, are as follows:

(A) the first acrylate derivative is preferably 14 to 89.49 parts byweight, more preferably 36 to 84.49 parts by weight, even morepreferably 39 to 59 parts by weight,

(B) the second acrylate derivative is preferably 0.1 to 50 parts byweight, more preferably 1 to 40 parts by weight; more specifically, (1)the low-molecular-weight derivative having a molecular weight of lessthan 1000 is 0.1 to 10 parts by weight, (2) the middle-molecular-weightderivative having a molecular weight of 1,000 to 4,000 is 0.5 to 20parts by weight, and (3) the high-molecular-weight derivative having amolecular weight of 4,000 or more is 1 to 50 parts by weight (morepreferably 10 to 40 parts by weight), and

(C) the acrylate derivative polymer is preferably 10 to 80 parts byweight, more preferably 15 to 60 parts by weight, even more preferably15 to 40 parts by weight.

When the amount of the component (A) is less than 14 parts by weight,there are cases where viscosity is increased, handleability isdeteriorated, bubbles are hardly removed, and bubbles are easilyentrained during coating. On the other hand, when the amount of thecomponent (A) is higher than 89.49 parts by weight, there are caseswhere viscosity is decreased, dripping occurs, necessary film thicknesscannot be secured, curing shrinkage is increased, smoothness isdeteriorated upon formation into a sheet, and distortion easily remainsupon direct coating and curing on a panel.

When the amount of the component (B) is less than 0.1 part by weight, acured product of the resin composition may hardly maintain its shape, onthe other hand, when the amount of the component (B) is higher than 50parts by weight, a cured product of the resin composition may becomebrittle to cause a problem in mechanical characteristics.

When the amount of the component (C) is less than 10% by weight, thereare cases where curing shrinkage is increased, smoothness isdeteriorated upon formation into a sheet, and distortion easily remainsupon direct coating and curing on a panel. On the other hand, when theamount of the component (C) is higher than 80 parts by weight, there arecases where viscosity is increased, bubbles are hardly removed, andbubbles are easily entrained during coating.

[(D) Polymerization Initiator]

When the optical resin composition of the present invention is subjectedto curing reaction, the optical resin composition preferably furthercontains (D) a polymerization initiator, wherein the amount of thecomponent (D), based on 100 parts by weight of (A) the first acrylatederivative, (B) the second acrylate derivative, (C) the acrylatederivative polymer, and (D) the polymerization initiator in total, ispreferably 0.01 to 5 parts by weight, more preferably 0.01 to 3 parts byweight, even more preferably 0.03 to 2 parts by weight. When the amountof the polymerization initiator is less than 0.01 part by weight, thereaction does not sufficiently proceed, on the other hand, when theamount of the polymerization initiator is higher than 5 parts by weight,the polymerization initiator will remain in a large amount to cause aproblem in optical characteristics or mechanical characteristics.

As (D) the polymerization initiator, it is possible to use (D1) aphotopolymerization initiator and/or (D2) a thermopolymerizationinitiator. When (D1) the photopolymerization initiator is used as (D)the polymerization initiator in the above composition, its use amount ispreferably 0.1 to 5 parts by weight. When the thermopolymerizationinitiator is used as the polymerization initiator, its use amount ispreferably 0.01 to 1 part by weight. When both the photopolymerizationinitiator and the thermopolymerization initiator are simultaneouslyused, they are used preferably in their respective amount ranges.

In the above composition, the high-molecular-weight crosslinking agentwhen used as (B) the second acrylate derivative is used preferably in anamount 1 part by weight or more, and the second acrylate derivativeshaving low-molecular weights to middle-molecular weights (particularlylow-molecular-weight monomers etc.) are used preferably in an amount 10parts by weight or less.

In the case of polymerization by irradiation with an electron beam, thepolymerization initiator may not be used. That is, the curing reactionmay be a curing reaction by irradiation with an active energy ray, or acuring reaction by heat, or both of them. The active energy ray refersto ultraviolet ray, electron beam, α-ray, β-ray, γ-ray, and the like.These methods can also be applied to synthesis of the acrylatederivative polymer.

In the present invention, (D1) the photopolymerization initiator can beselected from known materials such as benzophenone materials,anthraquinone materials, benzoin materials, sulfonium salts, diazoniumsalts, and onium salts. These materials have sensitivity particularly toultraviolet ray.

Specific examples of the photopolymerization initiator include aromaticketone compounds such as benzophenone,N,N′-tetramethyl-4,4′-diaminobenzophenone (Michler's ketone),N,N′-tetraethyl-4,4′-diaminobenzophenone,4-methoxy-4′-dimethylaminobenzophenone, α-hydroxyisobutylphenone,2-ethylanthraquinone, t-butylanthraquinone, 1,4-dimethylanthraquinone,1-chloroanthraquinone, 2,3-dichloroanthraquinone,3-chloro-2-methylanthraquinone, 1,2-benzoanthraquinone,2-phenylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone,thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl phenyl ketone,2,2-dimethoxy-1,2-diphenylethan-1-one, and2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin compounds such asbenzoin, methyl benzoin and ethyl benzoin, benzoin ether compounds suchas benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether andbenzoin phenyl ether, ester compounds such as benzyl, 2,2-diethoxyacetophenone, benzyl dimethyl ketal and β-(acridin-9-yl)acrylate,acridine compounds such as 9-phenyl acridine, 9-pyridyl acridine and1,7-diacridinoheptane, 2,4,5-triarylimidazole dimers such as2-(o-chlorophenyl)-4,5-diphenyl imidazole dimer,2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer,2-(o-fluorophenyl)-4,5-diphenylimidazole dimer,2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer,2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer,2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer,2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer, and2-(p-methylmercaptophenyl)-4,5-diphenylimidazole dimer,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone,2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propane,bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone), and thelike. Preferable examples of the photopolymerization initiator causingno coloration of the resin composition include α-hydroxyalkyl phenonecompounds such as 1-hydroxycyclohexyl phenyl ketone,2-hydroxy-2-methyl-1-phenyl-propan-1-one, and1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, acylphosphine oxide compounds such asbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphoshine oxide, and2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and mixtures ofoligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone),oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester andoxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, andcombinations thereof. Photopolymerization initiators that are preferablyused in preparation of particularly a thick sheet are those includingacyl phosphine oxide compounds such asbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphoshine oxide, and2,4,6-trimethylbenzoyl-diphenylphosphine oxide. For reducing the smellof a sheet, the photopolymerization initiators are preferably mixturesof oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone),oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester andoxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester. For reducingpolymerization inhibition by oxygen, the photopolymerization initiatorsare preferably mixtures of oxy-phenyl-acetic acid2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic acid2-[2-hydroxy-ethoxy]-ethyl ester. These photopolymerization initiatorsmay also be used in combination thereof.

(D2) The thermopolymerization initiator is an initiator that generates aradical by heating, and specific examples include organic peroxides suchas benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide,diisopropylperoxy dicarbonate, di-n-propylperoxy dicarbonate,di(2-ethoxyethyl)peroxy dicarbonate, t-butylperoxy neodecanoate,t-butylperoxy pivalate, t-hexylperoxy pivalate,(3,5,5-trimethylhexanoyl)peroxide, dipropionyl peroxide, lauroylperoxide, diacetyl peroxide and didodecyl peroxide. Other examplesinclude azo compounds such as 2,2′-azobisisobutyronitrile,2,2′-azobis(2-methylbutyronitrile), 1,1′-azobis(cyclohexane-1-carbonyl),2,2′-azobis(2,4-dimethylvaleronitrile),2,2′-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl2,2′-azobis(2-methylpropionate), 4,4′-azobis(4-cyanovaleric acid),2,2′-azobis(2-hydroxymethylpropionitrile), and2,2′-azobis[2-(2-imidazolin-2-yl)propane].

When the temperature at which half of the thermopolymerization initiatoris decomposed in 10 hours, called 10-hour half-life temperature, is toolow, storage stability may be reduced, while when the 10-hour half-lifetemperature is too high, there may arise a problem that because heatingat high temperature is necessary for the reaction, the characteristicsof a liquid crystal or a polarization plate are deteriorated, so thedisplay characteristics of the liquid crystal display are deteriorated.Accordingly, the 10-hour half-life temperature of thethermopolymerization initiator is preferably 40 to 80° C., morepreferably 40 to 65° C., even more preferably 50 to 65° C. Athermopolymerization initiator having a relatively high 10-hourhalf-life temperature can easily secure storage stability, but should beadded in a relatively large amount because of its low reactivity. On theother hand, a thermopolymerization initiator having a low 10-hourhalf-life temperature is added preferably in a relatively small amountto prevent polymerization reaction during storage.

The heating of the optical resin composition when applied or injected inthe state of a resin composition may not be allowable because of the lowheat resistance of a polarization plate used in a liquid crystal panel.In this case, a photopolymerization initiator capable of polymerizationwith light is preferable. In this case, the amounts of the respectivecomponents, based on 100 parts by weight of (A) the acrylate derivative,(B) the acrylate derivative polymer, (C) the high-molecular-weightcrosslinking agent and preferably (D1) the photopolymerization initiatorin total, are (A) 15 to 40 parts by weight, (B) 5 to 40 parts by weight,(C) 39 to 59 parts by weight and (D1) 0.5 to 2.0 parts by weight.

In the optical resin composition of the present invention, (A) the firstacrylate derivative is preferably a mixture consisting of an alkylacrylate having an alkyl group containing 4 to 18 carbons (referred tohereinafter as AA monomer) and a hydroxyl-containing acrylaterepresented by the following general formula (I) (referred tohereinafter as HA monomer):CH₂═CHCOO(C_(m)H_(2m)O)_(n)H  General Formula (I)wherein m is 2, 3 or 4, and n is an integer of 1 to 10.

(C) The acrylate derivative polymer is preferably a copolymer obtainedby polymerizing AA monomer with HA monomer.

The HA monomer is incorporated preferably such that the proportion (M %by mass) of HA monomer in (A) the first acrylate derivative and theproportion (P % by mass) of HA monomer in (C) the acrylate derivativepolymer satisfy the following relationship:−8≦(P−M)≦8  Formula (I)

In this case, the preferable amounts of the respective components in theoptical resin composition of the present invention, based on 100 partsby weight of (A) the first acrylate derivative, (B) the second acrylatederivative and (C) the acrylate derivative polymer in total, are asfollows: (A) the first acrylate derivative is contained in an amount ofpreferably 36 to 84.49 parts by weight, more preferably 39 to 69 partsby weight, even more preferably 39 to 59 parts by weight, (B) the secondacrylate derivative is contained in an amount of preferably 0.1 to 50parts by weight, more preferably 0.5 to 50 parts by weight, even morepreferably 1 to 40 parts by weight, and (C) the acrylate derivativepolymer is contained in an amount of preferably 15 to 60 parts byweight, more preferably 15 to 40 parts by weight, even more preferably40 to 60 parts by weight. As (B) the second acrylate derivative, morespecifically, (1) the low-molecular-weight derivative having a molecularweight of less than 1000 is preferably contained in an amount of 0.1 to10 parts by weight, (2) the middle-molecular-weight derivative having amolecular weight of 1,000 to 4,000 in an amount of 0.5 to 20 parts byweight, and (3) the high-molecular-weight derivative having a molecularweight of 4,000 or more in an amount of 1 to 50 parts by weight (morepreferably 10 to 40 parts by weight).

When (D) the polymerization initiator is further contained, (D) thepolymerization initiator based on 100 parts by weight of the components((A) to (C)) and (D) the polymerization initiator in total in the resincomposition is contained in an amount of preferably 0.01 to 5 parts byweight, more preferably 0.01 to 3 parts by weight, even more preferably0.03 to 2 parts by weight ((D1) the photopolymerization initiator iscontained in an amount of preferably 0.1 to 5 parts by weight, morepreferably 0.3 to 3 parts by weight, even more preferably 0.5 to 2.0parts by weight, and (D2) the thermopolymerization initiator iscontained in an amount of preferably 0.01 to 1 part by weight, morepreferably 0.01 to 0.5 part by weight, and when both (D1) thephotopolymerization initiator and (D2) the thermopolymerizationinitiator are used, they are used preferably in their respectiveranges).

In the above composition, the high-molecular-weight crosslinking agentwhen used as (B) the second acrylate derivative is used in an amount of1 part by weight or more, more preferably 5 parts by weight or more, andthe amount of the low-molecular weight to middle-molecular weight secondacrylate derivatives (particularly the low-molecular-weight monomeretc.) is preferably 10 parts by weight or less.

(A) The first acrylate derivative is preferably a compound having oneacryloyl group in its molecule, and this compound is preferably amixture of AA monomer and HA monomer, more preferably used in aproportion of 50 to 87% by weight of AA monomer and 13 to 50% by weightof HA monomer, even more preferably used in a proportion of 60 to 70% byweight of AA monomer and 30 to 40% by weight of HA monomer.

When the amount of AA monomer is higher than 87% by weight and thus theamount of HA monomer is too small, a cured product upon moistureabsorption becomes easily clouded, on the other hand, when the amount ofHA monomer is higher than 50% by weight and thus the amount of AAmonomer is too small, a cured product of the optical resin compositionof the present invention upon moisture absorption is easily deformed.

The HA monomer is preferably incorporated such that the proportion (M %by mass) of HA monomer in (A) the first acrylate derivative and theproportion (P % by mass) of HA monomer in (C) the acrylate derivativepolymer satisfy the following relationship:−8≦(P−M)≦8  Formula (I)

When (P−M) does not satisfy the above relationship, the optical resinmaterial of the present invention tends to be easily clouded uponcuring. This condition is always satisfied when AA monomer (and HAmonomer) are in the preferable proportions described above in (C) theacrylate derivative polymer and (A) the first acrylate derivative.

The value of (P−M) preferably has a lower limit of −5 and an upper limitof 5, more preferably a lower limit of −3 and an upper limit of 3.

The AA monomer includes n-butyl acrylate, n-pentyl acrylate, n-hexylacrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate,dodecyl acrylate, stearyl acrylate, and the like, among which n-butylacrylate, isooctyl acrylate, 2-ethylhexyl acrylate and n-octyl acrylateare preferable, and ethylhexyl acrylate is particularly preferable.These acrylates may be used as a combination of two or more thereof.

The HA monomer includes hydroxyl-containing acrylates such as2-hydroxyethyl acrylate, 1-hydroxyethyl acrylate, 2-hydroxypropylacrylate, 3-hydroxypropyl acrylate, 1-hydroxypropyl acrylate,4-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, 2-hydroxybutylacrylate and 1-hydroxybutyl acrylate, polyethylene glycol monoacrylatessuch as diethylene glycol or triethylene glycol, polypropylene glycolmonoacrylates such as dipropylene glycol or tripropylene glycol, andpolybutylene glycol monoacrylates such as dibutylene glycol ortributylene glycol, among which 2-hydroxyethyl acrylate, 1-hydroxyethylacrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate,1-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 3-hydroxybutylacrylate, 2-hydroxybutyl acrylate and 1-hydroxybutyl acrylate arepreferable, and 2-hydroxyethyl acrylate is particularly preferable.These acrylates may be used as a combination of two or more thereof.

In the present invention, the AA monomer and HA monomer are usedpreferably as the same combination in (A) the first acrylate derivativeand (C) the acrylate derivative polymer, respectively.

The copolymer obtained by polymerizing the AA monomer with the HAmonomer in the present invention has a weight-average molecular weight(determined by using a calibration curve of standard polystyrenes by gelpermeation chromatography; this applies hereinafter) of preferably100,000 to 700,000, more preferably 150,000 to 400,000, still morepreferably 200,000 to 350,000.

As the method of synthesizing the copolymer obtained by polymerizing theAA monomer with the HA monomer, it is possible to use knownpolymerization methods, such as solution polymerization, suspensionpolymerization, emulsion polymerization and bulk polymerization, amongwhich solution polymerization or bulk polymerization is preferable. Asthe polymerization initiator, a compound generating a radical by heatcan be used. Specific examples include organic peroxides such as benzoylperoxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxy dicarbonate, di(2-ethoxyethyl)peroxydicarbonate, t-butylperoxy neodecanoate, t-butylperoxy pivalate,(3,5,5-trimethylhexanoyl)peroxide, dipropionyl peroxide, diacetylperoxide and didodecyl peroxide, and azo compounds such as2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methylbutyronitrile),1,1′-azobis(cyclohexane-1-carbonyl),2,2′-azobis(2,4-dimethylvaleronitrile),2,2′-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl2,2′-azobis(2-methylpropionate), 4,4′-azobis(4-cyanovaleric acid),2,2′-azobis(2-hydroxymethylpropionitrile), and2,2′-azobis[2-(2-imidazolin-2-yl)propane].

The polymerization of the AA monomer at a proportion of 50 to 87% byweight with the HA monomer at 13 to 50% by weight is preferable, and thepolymerization of the AA monomer at 60 to 70% by weight with the HAmonomer at 30 to 40% by weight is more preferable.

From the viewpoint of deterioration prevention, thermal stability,moldability and processability, the optical resin composition of thepresent invention may be compounded with antioxidants based on phenol,phosphite, and thioether, release agents such as aliphatic alcohols,fatty acid esters, phthalates, triglycerides, fluorochemicalsurfactants, and higher fatty metal salts, other lubricants,plasticizers, antistatic agents, ultraviolet absorbers, flameretardants, heavy-metal deactivators, fine granular fillers such asalumina, silica, magnesium oxide, talc, barium titanate, and bariumsulfate, and coloring agents including dyes such as Victoria Pure Blueand pigments such as phthalocyanine green, in such a range that opticalcharacteristics or the working effect of the present invention is notsignificantly deteriorated. Also, compounds having one polymerizableunsaturated bond in its molecule, such as acrylonitrile, styrene, vinylacetate, ethylene, and propylene may also be used as components otherthan the components (A) to (D).

Preferably the optical resin composition of the present invention isfurther added with various stabilizers as necessary. The stabilizersinclude polymerization inhibitors such as paramethoxy phenol used forthe purpose of improving the storage stability of the resin composition,antioxidants such as triphenyl phosphine used in improving the heatresistance of a cured product of the resin composition, and HALS etc.used for improving weatherability. These stabilizers may be used as acombination of one or more thereof. Besides, other compounds may beadded in such a range that the effect of the present invention can beattained.

The curing shrinkage of the optical resin composition of the presentinvention is preferably 15% or less, more preferably 12% or less. Whenthe curing shrinkage is high, stress by shrinkage is increased thusgenerating distortion in the resin or causing the resin to be easilyreleased from a protective plate or a liquid crystal panel.

The optical resin composition of the present invention is formed into afilm or a layer on an optical filter or on the surface of an imagedisplay panel of an image display device, such that its film thicknesspreferably reaches 0.1 mm to 3 mm. In consideration of impactabsorption, the thickness is more preferably 0.2 mm or more.Particularly when impact absorption is to be increased, the thickness ispreferably 1.3 mm or more. The optical resin composition of the presentinvention can be applied onto the surface of an image display panel oran image display device, a substrate of an optical filter, or the like,may be applied to form a film thereon, then cured by irradiation with alight such as ultraviolet ray or a radiation such as electron beam, toform an optical resin material. When an optical filter is prepared, theoptical resin composition of the present invention is formed into a filmon a substrate of the optical filter or on a functional layer such as anantireflective film, further laminated with a substrate of the opticalfilter, a functional layer or a protective layer, and then cured byirradiation with a radiation. The optical resin composition of thepresent invention may, when possible, be used in the form of a sheet(including form of a film).

<Optical Resin Material>

The optical resin material of the present invention can be obtained bycuring reaction of the optical resin composition of the presentinvention. The optical resin composition may be applied to form a filmon the surface of an image display panel or an image display device, ona substrate of an optical film, or the like, and then cured byirradiation with light or by heating to a predetermined temperature.Heating and light irradiation may be simultaneously used.

As the method of synthesizing the acrylate derivative polymer, it ispossible to use known polymerization methods, such as solutionpolymerization, suspension polymerization, emulsion polymerization andbulk polymerization.

The produce of the optical resin material of the present invention canmake use of injection molding for example, by applying the resincomposition to a desired thickness with a general-purpose coater andthen curing it by irradiation with a light such as ultraviolet ray or aradiation such as electron beam. When the material is in the form of asheet (including in form of a film), the thickness of the sheet ispreferably 0.1 mm to 3 mm. When a transparent protective substrate isnot used, the thickness of the sheet is more preferably 0.2 mm or morein consideration of impact absorption. Particularly when impactabsorption is to be increased, the thickness is preferably 1.3 mm ormore. On the other hand, when a transparent protective substrate isused, the thickness of the sheet is preferably 0.5 mm or less, morepreferably 0.2 mm or less. This optical resin material can be laminatedin the form of a sheet (including a film) such as on the surface of animage display panel or an image display device or on an optical filter,directly or via a pressure-sensitive adhesive or an adhesive.

When an optical filter is to be produced, the optical resin compositionof the present invention can be applied onto a substrate of an opticalfilter or a functional layer such as an antireflective film layer toform a film thereon, then laminated with a substrate of an opticalfilter, a functional layer or a protective layer and then cured byirradiation with a radiation. The optical resin composition of thepresent invention may, when possible, be used in the form of a sheet(including the form of a film) and then cured.

The glass transition temperature (Tg) of the optical resin material usedin the present invention is preferably 0° C. or less. When the glasstransition temperature is higher than 0° C., the impact-absorbing layeris made rigid and easily ruptured by impact. The Tg is more preferably−20 to −60° C.

In the molecule of the polymer serving as the optical resin materialused in the present invention is preferably provided with a polar groupfor the purpose of increasing adhesiveness. The polar group forincreasing adhesiveness to glass includes polar groups such as ahydroxyl group, a carboxyl group, a cyano group and a glycidyl group,and these groups can be introduced by reacting the molecule with amonomer having such a group.

The rubber hardness of the optical resin material of the presentinvention is preferably 50 or less.

A sample of 40 mm in width, 40 mm in length and 10 mm in depth ismeasured for its rubber hardness and used at 5 positions with aspring-type hardness meter (for example, WR-104A manufactured by NishiTokyo Seimitsu Co., Ltd.), and an average value at the 5 positions isindicated as rubber hardness.

The storage elastic modulus of the optical resin material of the presentinvention is preferably 10⁴ to 10⁷ Pa at 25° C. in order to support aprotective plate and to absorb impact.

The birefringence of the optical resin material of the present inventionis preferably 30 nm or less, more preferably 10 nm or less. When thebirefringence is large, irregular color tends to easily occur uponlighting of a liquid crystal panel.

The optical resin composition and the optical resin material accordingto the present invention, when used in image display devices, have avisible light transmittance of preferably 50% or more, more preferably80% or more, even more preferably 85% or more. When the total lighttransmittance is too low, contrast tends to decrease and visibilitytends to decrease.

When the polymerization of the optical resin composition of the presentinvention by irradiation with ultraviolet ray or the like is inhibitedby the presence of oxygen, the surface of the resin is preferablycovered with a transparent film or transparent glass to shield oxygen.By polymerization in an inert atmosphere, oxygen can also be shielded.When oxygen is difficult to shield, the influence of oxygen onpolymerization inhibition can be reduced by increasing the amount of apolymerization initiator added. The polymerization initiator in thiscase is preferably a mixture of oxy-phenyl-acetic acid2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic acid2-[2-hydroxy-ethoxy]-ethyl ester. An ultraviolet irradiator that can beused includes sheet-feeding or conveyor-type ultraviolet irradiators.Alight source that can be used in ultraviolet irradiation includes alow-pressure mercury lamp, a medium-pressure mercury lamp, ahigh-pressure mercury lamp, a metal halide lamp and a LED lamp, amongwhich a high-pressure mercury lamp and a metal halide lamp arepreferable.

Even if the optical resin composition of the present invention is formedinto a thick film or the optical resin material of the present inventionis thick, it includes a high-molecular-weight copolymer (component (C)),and thus the optical resin material as its cured resin is rigid, ishardly composition deformable against impact, and can thus be madethicker to easily improve impact absorption.

The optical resin composition or the optical resin material according tothe present invention can be applied to various image display devices.The image display devices include plasma display panel (PDP), liquidcrystal display (LCD), cathode ray tube (CRT), field emission display(FED), organic EL display, electronic paper, and the like.

<Optical Filter>

The optical filter of the present invention can be constituted bycombining the optical resin composition or the optical resin material ofthe present invention with a multilayer material having a functionallayer such as an antireflective layer, an antifouling layer, a coloringlayer, a hard coat layer, or the like, formed as a film or layer on asubstrate film such as a polyethylene film or a polyester film, or witha plate such as glass, acrylate or polycarbonate, or with a multilayermaterial having a functional layer formed as a film or layer on such aplate, or with such a plate or multilayer material.

The antireflective layer may be a layer having an antireflectionproperty to reduce the visible reflectance of the optical filter to 5%or less, and may be a layer treating a transparent substrate such as atransparent plastic film by an known antireflection method.

The antifouling layer is used to make the surface of the optical filterantifouling, and a layer of a fluorine-based resin, a silicon-basedresin, or the like, is used to decrease surface tension, and these knownlayers can be used.

The coloring layer is used for improving color purity and used inreducing unnecessary light when the color purity of light emitted froman image display panel such as a liquid crystal display panel. Acoloring matter that absorbs an unnecessary portion of light isdissolved in a resin and formed into a film or layer on a substrate filmsuch as a polyethylene film or a polyester film or is mixed with apressure-sensitive adhesive.

The hard coat layer is used to increase surface hardness. As the hardcoat layer, acrylic resin such as urethane acrylate or epoxy acrylate,epoxy resin, or the like, can be formed into a film or layer on asubstrate film such as polyethylene film. Similarly, a glass plate, anacrylic plate, a plate of polycarbonate, or the like, or a hard coatlayer formed into a film or laminated on such a plate can also be usedto increase surface hardness.

In the optical resin composition or the optical resin material of thepresent invention, a functional layer such as an antireflective layerand an appropriately necessary layer can used by lamination. In thiscase, the functional layer may be laminated on one side of a transparentsubstrate, or layers different in function or layers having the samefunction may be laminated on both sides of a transparent substrate. Thefunctional layers may be arranged in an arbitrary order.

The optical resin composition or optical resin material of the presentinvention, when combined with these functional layers, is laminatedpreferably in a side near to an image display panel or the surface of animage display device.

The optical filter of the present invention can also be obtained bylaminating the optical resin composition or optical resin material ofthe present invention on a polarization plate. In this case, the opticalresin composition or material may be formed into a film or layer at theviewable side, or the other side, of a polarization plate. When theoptical resin composition or optical resin material of the presentinvention is used at the viewable side of a polarization plate, anantireflective layer, an antifouling layer and a hard coat layer may belaminated nearer to the viewable face than the optical resin compositionor material. When the optical resin composition or material is usedbetween a polarization plate and a liquid crystal cell, functionallayers can be laminated at the viewable side of the polarization plate.

When such a multilayer material is formed, the optical resin compositionor optical resin material of the present invention is arrangedpreferably as the outermost layer.

If necessary, these layers may be laminated via pressure-sensitiveadhesive layers among the layers by a roller laminator or a sheetfeeding laminator. The multilayer material laminated by a rollerlaminator or a sheet feeding laminator can be laminated by a rollerlaminator or a sheet feeding laminator on an image display panel or infront of an image display device or on a front plate or a transparentprotective substrate for an image display device.

<Image Display Device>

In the image display device of the present invention, a layer consistingof the optical resin composition or optical resin material of thepresent invention is arranged in a suitable position at the viewableside. Particularly it is applied between an image display panel and afront plate or a transparent protective substrate, is particularlypreferred.

The front plate or transparent protective substrate for an image displaydevice can use a general optical transparent substrate. Specificexamples include an inorganic plate such as a glass plate or a quartzplate, a resin plate such as an acrylic resin plate, a cycloolefin resinplate or a polycarbonate plate, and a resin sheet such as a thickpolyester sheet. When high surface hardness is necessary, a plate suchas a glass plate or an acrylic plate is preferable, and a glass plate ismore preferable. The front plate or the surface of the transparentprotective substrate may have been subjected thereon to antireflectiontreatment and antifouling treatment or provided with a hard coat. Oneside or both sides of the front plate or the transparent protectivesubstrate may have been subjected to these surface treatments. Acombination of these front plates or transparent protective substratesmay also be used.

The front plate or transparent protective substrate for an image displaydevice preferably has a pencil hardness of H or more and a birefringenceof 50 nm or less. When the pencil hardness is low, the surface may bescarred or easily ruptured by impact. When the birefringence is high,irregular color tends to easily occur. When the optical resincomposition is a ultraviolet curable resin composition, the front plateor transparent protective substrate for an image display devicepreferably has a ultraviolet transmittance of 1% or more at a wavelengthof 365 nm. When the ultraviolet transmittance is low, the ultravioletcurable resin composition becomes easily deficient in curing and reducesreliability.

When the image display device of the present invention is a liquidcrystal display, its liquid crystal display cell may use a generalliquid crystal display cell. The liquid crystal display cell can bedivided, depending on the control method, into TN, STN, VA, IPS etc.,and liquid crystal display cells using any of the control methods may beused.

The liquid crystal display will be described in detail by reference tothe drawings. FIGS. 1, 2, 3 and 4 are schematic cross-sectional views ofliquid crystal displays using the optical resin material of the presentinvention, and FIGS. 5 and 6 are schematic cross-sectional views ofconventional liquid crystal displays.

The structure of the conventional liquid crystal display as shown in oneexample in FIG. 5 is composed of a liquid crystal display cell 1,polarization plates 2 stuck to both sides thereof, and a transparentprotective substrate 5 arranged via gap 3 in the front. The liquidcrystal display cell 1 is a structure having a liquid crystalencapsulated between two transparent glass plates, and polarizationplates 2 etc. are attached outside of the glass plates on both sides.Reference numeral 4 positioned below the liquid crystal display cell 1is a reflective plate or a backlight system. In this case, anantireflective layer, an antifouling layer, a hard coat layer and thelike are laminated as necessary in front of the transparent protectivesubstrate 5. FIG. 6 shows another conventional liquid crystal display,which includes a liquid crystal display cell 1, polarization plates 2stuck to both sides thereof, and a reflective plate or a backlight unit4. In this case, an antireflective layer, an antifouling layer, a hardcoat layer and the like are laminated as necessary in front of thepolarization plate 2. On the other hand, a liquid crystal displaycomposed by using a transparent resin layer consisting of the opticalresin material of the present invention is shown in FIG. 1 as oneexample of the liquid crystal display of the present invention.

Polarization plates 2 are laminated on both sides of the liquid crystaldisplay cell 1, a transparent resin layer 3′ is laminated on one of thepolarization plates 2, and a transparent protective substrate 5 islaminated thereon to constitute a viewable side, while a reflectiveplate or a backlight system 4 is arranged on the other polarizationplate 2.

The order of the transparent resin layer 3′ and the polarization plate 2at the viewable side in the structure shown in FIG. 1 may be changed asshown in FIG. 2. In this case, a pressure-sensitive adhesive or the likemay be used to stick the polarization plate 2 to the transparentprotective substrate 5. When the transparent protective substrate 5 isused as shown in FIG. 1 or 2, the surface of the transparent protectivesubstrate 5 may be laminated thereon as necessary with an antireflectivelayer, an antifouling layer, a hard coat layer and the like. The surfaceof the polarization plate 2 may be laminated thereon as necessary withan antireflective layer, an antifouling layer, a hard coat layer and thelike, but these functional layers may be lacking.

There are also structures where the transparent protective substrate 5is not arranged as shown in FIGS. 3 and 4, corresponding to thestructures of the liquid crystal displays in FIGS. 1 and 2. In FIG. 4,the order of the transparent resin layer 3′ and the polarization plate 2is changed. When the polarization plate 2 is arranged as the outermostlayer as shown in FIG. 3, an antireflective layer, an antifouling layer,a hard coat layer and the like may be laminated on the surface of thepolarization plate 2. When the transparent resin layer 3′ is arranged asthe outermost layer as shown in FIG. 4, an antireflective layer, anantifouling layer, a hard coat layer and the like may be laminated infront of the transparent resin layer 3′, and at least a hard coat layeris particularly preferably laminated.

The polarization plate may use a general polarization plate. The surfaceof the polarization plate may have been subjected to antireflectiontreatment, antifouling treatment or provided with a hard coat. One sideor both sides of the polarization plate may have been subjected to suchsurface treatments.

The optical resin composition or the optical resin material of thepresent invention is formed into a film or layer laminated on functionallayers such as an antireflective layer, an electromagnetic shieldinglayer and an infrared shielding layer or on substrate films such as apolyethylene film and a polyester film and can be utilized as amultilayer material or as an optical filter consisting of suchmultilayer material.

The electromagnetic shielding layer may be a known electromagneticshielding layer as long as it has a visible reflectance of 60% or moreas electromagnetic shielding property. A transparent electroconductivefilm, an electroconductive fiber mesh, a mesh prepared fromelectroconductive ink, etc. can be used, but from the viewpoint of hightransparency and high electromagnetic shielding property, a metal meshis most preferable. For preparation of a metal mesh, a transparentsubstrate such as polyester film and an electroconductive foil such ascopper foil or aluminum foil are stuck to each other via an adhesiveapplied to either or both of them, and then the metal foil is etched bythe chemical etching process, to produce the intended metal mesh. Atthis time, the electroconductive metal foil is preferably using onehaving a rough surface for securing adhesiveness. The rough surface ofthe electroconductive metal foil is laminated so as to face the adhesivelayer. After the metal mesh is prepared by etching as described above,it is preferable that a resin particularly preferably a resin curablewith radiations such as ultraviolet ray, electron beam etc. is appliedonto the metal mesh and then cured by irradiation with radiations suchas ultraviolet ray, electron beam etc., whereby the adhesive layer towhich the rough surface was transferred is made transparent. The resincomposition of the present invention can be used as a resin forattaining transparency or as a resin both for transparency and as animpact absorbing layer.

The antireflective layer may be a layer having antireflective propertyto attain a visible reflectance of 5% or less, and can be a layerprepared by treating a transparent substrate such as a transparentplastic film by a known antireflective method.

The infrared shielding layer consists of a resin layer having aninfrared absorber such as an imonium salt or an infrared shieldingmaterial dispersed therein, and can be laminated on a transparentsubstrate such as a transparent plastic film. The optical resincomposition or the optical resin sheet of the present invention can beendowed with an ability to shield infrared light by dispersing aninfrared absorber such as an imonium salt or an infrared shieldingmaterial therein.

The filter having an electromagnetic shielding layer or an infraredshielding layer is suitable for a plasma display.

In the layer having the optical resin composition or the optical resinmaterial according to the present invention and functional layers suchas an electromagnetic shielding layer, an antireflective layer and aninfrared shielding layer, a layer consisting of the optical resincomposition or the optical resin material of the present invention isessential and other necessary layers can be used by lamination. In thiscase, the functional layer may be laminated on one side of a transparentsubstrate, or layers different in function or layers having the samefunction may be laminated on both sides of a transparent substrate. Theorder of functional layers to be laminated is arbitrary.

When such multilayer material is to be formed, the optical resincomposition or the optical resin material of the present invention isarranged preferably as the outermost layer. In this case, the opticalresin composition or the optical resin material of the present inventioncan be stuck, via its adhesion, to a panel, a transparent substrate etcas necessary by the user. On the other hand, it can be previouslylaminated on a transparent substrate or the like so that a sticking stepto be conducted by the user can be eliminated.

These layers can be laminated via a pressure-sensitive layer among thelayers by a roller laminator or a sheet feeding laminator. Themultilayer material laminated by a roller laminator or a sheet feedinglaminator can be laminated, by a roller laminator or a sheet feedinglaminator, on the front of an image display device or an image displaypanel or on a front plate for an image display device. In this case, alayer consisting of the optical resin material of the present inventionis preferably stuck to the front of an image display or an image displaypanel or on a front plate for an image display device. The image displaydevice or the image display device includes PDP, liquid crystal display(LCD) panel, cathode ray tube (CRT), and the like.

EXAMPLES

Hereinafter, the present invention is described by reference to theExamples. The present invention is not limited to these examples.

Example 1 Synthesis of Acrylate Derivative Polymer

In a reaction container equipped with a condenser, a thermometer, astirrer, a dropping funnel and a nitrogen inlet tube, 84.0 g of2-ethylhexyl acrylate (AA monomer), 36.0 g of 2-hydroxyethyl acrylate(HA monomer) and 150.0 g of methyl isobutyl ketone were heated asinitial monomers from ordinary temperature to 70° C. over 15 minuteswhile the atmosphere in the reaction container was replaced withnitrogen at a gas flow rate of 100 ml/min. To this solution kept at thistemperature was dropped a solution prepared by dissolving 0.6 g oflauroyl peroxide in 21.0 g of 2-ethylhexyl acrylate and 9.0 g of2-hydroxyethyl acrylate as additional monomers over 60 minutes, andafter completion of dropping, the mixture was further reacted for 2hours. Subsequently, a 2-ethylhexyl acrylate (AA monomer)/2-hydroxyethylacrylate (HA monomer) copolymer (weight-average molecular weight of250,000) was obtained by distilling away the methyl isobutyl ketone.

(Synthesis of High-Molecular-Weight Crosslinking Agent)

Then, 180 g of polypropylene glycol (molecular weight 2,000), 2.33 g of2-hydroxyethyl acrylate, 0.5 g of p-methoxyphenol as a polymerizationinhibitor, and 0.05 g of dibutyltin dilaurate as a catalyst were placedin a reaction container equipped with a condenser, a thermometer, astirrer, a dropping funnel and an air inlet tube and heated to 70° C.under passage of air, and then 22.2 g of isophorone diisocyanate wasuniformly dropped thereto over 2 hours under stirring at 70 to 75° C.,to carry out the reaction. When the mixture was reacted for about 5hours after completion of dropping and then measured by IR, thedisappearance of the isocyanate was confirmed, and the reaction wasterminated to yield polyurethane acrylate (weight-average molecularweight 16,000) having polypropylene glycol and isophorone diisocyanateas repeating units and having polymerizable unsaturated bonds at bothends.

(Preparation of Optical Resin Composition to Preparation of TransparentSheet)

The above copolymer 24.88 g 2-Ethylhexyl acrylate (AA monomer) 27.85 g2-Hydroxyethyl acrylate (HA monomer) 11.94 g The above polyurethaneacrylate 34.84 g 1-Hydroxy-cyclohexyl-phenyl-ketone  0.50 g(photopolymerization initiator)

The above components were stirred and mixed to prepare (1) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. The curing shrinkage of thisresin composition was 5.3%, and the sheet had a total lighttransmittance of 92% and a birefringence of 0.4 nm. Then, this sheet wasstuck to a float glass of 2.8 mm in thickness for shield glass, furtherstuck to a glass of 0.7 mm in thickness, and subjected to an impactresistance test. As a result, the shield glass was not broken at 0.6 Jbut broken at 0.75 J. This sheet maintained transparency even after amoisture absorption test. The impact resistance test was carried out inthe following manner.

—Impact Resistance Test—

The resin sheet stuck to shield glass was further stuck to a glass of0.7 mm in thickness equivalent to that used in a liquid crystal panel,and 510 g steel ball was dropped to the side of the shield glass, toevaluate its impact resistance. The steel ball was dropped from thecenter heights of 5 cm, 8 cm, 10 cm, 12 cm, 15 cm, and thereafter fromheights increased by 5 cm increments, and impact resistance wasevaluated depending on whether the shield glass was broken or not. Theimpact strength was calculated from the following equation:Impact strength=steel ball weight (Kg)×height (m)×9.8 (m/s²)

For example, when the height is 5 cm, the impact strength is0.51×0.05×9.8=0.25 J.

The resulting optical resin composition was poured into a frame of 40 mmin width, 40 mm in length and 10 mm in depth, and the composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 9,000 mJ ultraviolet ray from an ultravioletirradiator, to prepare a sample for rubber hardness measurement, andthis sample when measured for its rubber hardness indicated a rubberhardness of 2.

Example 2

The copolymer in Example 1 39.60 g 2-Ethylhexyl acrylate (AA monomer)31.88 g 2-Hydroxyethyl acrylate (HA monomer) 13.66 g The polyurethaneacrylate in Example 1 13.86 g 1-Hydroxy-cyclohexyl-phenyl-ketone  1.0 g(photopolymerization initiator)

The above components were stirred and mixed to prepare (2) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. The curing shrinkage of thisresin composition was 5.9% and the total light transmittance of thesheet was 91%. Then, this sheet was stuck to a float glass of 2.8 mm inthickness for shield glass, further stuck to a glass of 0.7 mm inthickness, and subjected to an impact resistance test in the same manneras in Example 1. As a result, the shield glass was not broken at 0.5 Jbut broken at 0.75 J. This sheet maintained transparency even after amoisture absorption test.

The resin composition was poured into a frame of 40 mm in width, 40 mmin length and 10 mm in depth, and the resin composition in a statecovered at an upper part with an ultraviolet transmitting glass wasirradiated with 9,000 mJ ultraviolet ray from an ultraviolet irradiator,to prepare a sample for rubber hardness measurement, and this samplewhen measured for its rubber hardness indicated a rubber hardness of 0.

Example 3

The copolymer in Example 1 24.50 g 2-Ethylhexyl acrylate (AA monomer)27.44 g 2-Hydroxyethyl acrylate (HA monomer) 11.76 g The polyurethaneacrylate in Example 1 34.30 g A mixture (photopolymerization initiator)of oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl esterand  2.00 g oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester)

The above components were stirred and mixed to prepare (3) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. The curing shrinkage of thisresin composition was 5.4%, and the sheet had a total lighttransmittance of 91% and a birefringence of 0.4 nm. Then, this sheet wasstuck to a float glass of 2.8 mm in thickness for shield glass, furtherstuck to a glass of 0.7 mm in thickness, and subjected to an impactresistance test in the same manner as in Example 1. As a result, theshield glass was not broken at 0.5 J but broken at 0.75 J. This sheetmaintained transparency even after a moisture absorption test.

The resin composition was poured into a frame of 40 mm in width, 40 mmin length and 10 mm in depth, and the resin composition in a statecovered at an upper part with an ultraviolet transmitting glass wasirradiated with 9,000 mJ ultraviolet ray from an ultraviolet irradiator,to prepare a sample for rubber hardness measurement, and this samplewhen measured for its rubber hardness indicated a rubber hardness of 0.Separately, the resin composition was poured into a frame of 100 mm inwidth, 100 mm in length and 0.5 mm in depth, and the resin compositionin a state not covered at an upper part was irradiated with 2,000 mJultraviolet ray from an ultraviolet irradiator to yield a transparentsheet.

When examined by touch, there did not occur stringing on the surface.

Example 4 Synthesis of High-Molecular-Weight Crosslinking Agent

520.80 g of polytetramethylene glycol (molecular weight 850), 1.06 g ofdiethylene glycol, 275.20 g of unsaturated fatty acid hydroxyalkylester-modified ε-caprolactone (Plaqucell FA2D, DAICEL CHEMICALINDUSTRIES, LTD.), 0.5 g of p-methoxyphenol as a polymerizationinhibitor, and 0.3 g of dibutyltin dilaurate as a catalyst were placedin a reaction container equipped with a condenser, a thermometer, astirrer, a dropping funnel and an air inlet tube, and then heated to 70°C. Then, 222 g of isophorone diisocyanate was uniformly dropped theretoover 2 hours under stirring at 70 to 75° C., to carry out the reaction.When the mixture was reacted for about 5 hours after completion ofdropping and then measured by IR, the disappearance of the isocyanatewas confirmed, and the reaction was terminated to yield polyurethaneacrylate having a weight-average molecular weight of 7,000.

(Preparation of Optical Resin Composition to Preparation of TransparentSheet)

The copolymer in Example 1 47.00 g 2-Ethylhexyl acrylate (AA monomer)33.25 g 2-Hydroxyethyl acrylate (HA monomer) 14.25 g The abovepolyurethane acrylate  5.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone  0.50 g(photopolymerization initiator)

The above components were stirred and mixed to prepare (4) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. The curing shrinkage of thisresin composition was 5.4%, and the sheet had a total lighttransmittance of 92% and a birefringence of 0.4 nm. Then, this sheet wasstuck to a float glass of 2.8 mm in thickness for shield glass, furtherstuck to a glass of 0.7 mm in thickness, and subjected to an impactresistance test in the same manner as in Example 1. As a result, theshield glass was not broken at 0.5 J but broken at 0.75 J. This sheetmaintained transparency even after a moisture absorption test.

The resin composition was poured into a frame of 40 mm in width, 40 mmin length and 10 mm in depth, and the resin composition in a statecovered at an upper part with an ultraviolet transmitting glass wasirradiated with 9,000 mJ ultraviolet ray from an ultraviolet irradiator,to prepare a sample for rubber hardness measurement, and this samplewhen measured for its rubber hardness indicated a rubber hardness of 1.

Example 5

A sheet prepared in the same manner as in Example 1 was stuck to a floatglass of 6.0 mm in thickness for shield glass, further stuck to a glassof 0.7 mm in thickness, and subjected to an impact resistance test inthe same manner as in Example 1. As a result, the shield glass was notbroken at 2.75 J but broken at 3.0 J.

Example 6

A sheet prepared in the same manner as in Example 1 was stuck to a floatglass of 1.3 mm in thickness for shield glass, further stuck to a glassof 0.7 mm in thickness, and subjected to an impact resistance test inthe same manner as in Example 1. As a result, the shield glass was notbroken at 0.4 J but broken at 0.5 J.

Example 7

A strip of 0.5 mm in thickness and 5 mm in width was stuck as a frame toall sides of an AG-treated polarization plate stuck to the surface of aliquid crystal display cell of 32 inches in diagonal length. (1) Thesame optical resin composition as in Example 1 was poured into theframe, and then its surface was covered with a soda glass of 32 inchesin diagonal length and 2.8 mm in thickness on which an antireflectivelayer had been formed to prevent the inclusion of bubbles. Then, theresin was cured by exposure with an integrated exposure of 2,000 mJultraviolet ray from a conveyor ultraviolet irradiator using a metalhalide lamp, thereby giving a liquid crystal display cell having anoptical resin material and a transparent protective substrate (sodaglass). This liquid crystal display cell was set in a body having abacklight unit and a driving circuit to produce a liquid crystaldisplay. This liquid crystal display was free of color change resultingfrom coloring of the resin material therein and did not show releasingor floating, in the interface, of the optical resin material or thetransparent protective substrate. There was no image deterioration dueto ghost image, and upon touching the surface, there was no imagedeterioration attributable to sagging of the panel.

Example 8

A sheet prepared in the same manner as in Example 1 was stuck to theelectromagnetic shielding layer side of a substrate film in anelectromagnetic shielding film U (TT42-01) A manufactured by HitachiChemical Co., Ltd. to prepare an optical filter having electromagneticshielding property. When this filter was measured for its impactresistance test in the following manner, the glass was not broken withan impact of 0.8 J but broken with an impact of 0.9 J. Breakage of theresin sheet was not observed.

—Impact Resistance Test—

The resin sheet stuck to the electromagnetic shielding film was furtherstuck to a soda glass of 2.8 mm in thickness, and a steel ball wasdropped onto it to evaluate impact resistance. The impact was increasedby 0.1 J increments, and the strength of impact just before the glass orthe resin sheet had been broken was regarded as impact resistance.

Example 9

A sheet prepared in the same manner as in Example 2 was stuck to theelectromagnetic shielding layer side of a substrate film in anelectromagnetic shielding film U (TT42-01) A manufactured by HitachiChemical Co., Ltd. and subjected to an impact resistance test in thesame manner as in Example 8. As a result, the glass was not broken withan impact of 0.9 J but broken with an impact of 1.0 J. Breakage of theresin sheet was not observed.

Example 10

(1) The optical resin composition in Example 1 was applied onto apolyester film, then covered with a cover film, and irradiated withultraviolet to produce a sheet of 42-inch size. This sheet was laminatedby a roller laminator on a transparent resin layer of an electromagneticshielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd.to prepare an electromagnetic shielding film with an impact-absorbinglayer. The substrate polyester film side of the electromagneticshielding film was further laminated by a roller laminator on anantireflective film having an infrared shielding function or a visiblelight wavelength selection absorption function (Clearlas NIR-SA,manufactured by SUMITOMO OSAKA CEMENT Co., Ltd.) to manufacture adirectly stuck filter for plasma display. This directly stuck filter wasstuck by a laminator to a plasma display panel via the adhesion of theimpact-absorbing layer, and when an image was displayed, a displayexcellent in contrast without a ghost image was obtained.

Reference Example 1 Preparation of Optical Resin Composition toPreparation of Transparent Sheet

The copolymer in Example 1  31.5 g 2-Ethylhexyl acrylate 26.95 g2-Hydroxyethyl acrylate 11.55 g 1,6-Hexanediol diacrylate 30.00 g1-Hydroxy-cyclohexyl-phenyl-ketone  0.50 g

The above components were stirred and mixed to prepare (5) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. Then, this sheet was stuck to afloat glass of 2.8 mm in thickness for shield glass, further stuck to aglass of 0.7 mm in thickness, and subjected to an impact resistance testin the same manner as in Example 1. As a result, the shield glass wasbroken at 0.25 J. This sheet maintained transparency even after amoisture absorption test.

The resin composition was poured into a frame of 40 mm in width, 40 mmin length and 10 mm in depth, and the resin composition in a statecovered at an upper part with an ultraviolet transmitting glass wasirradiated with 9,000 mJ ultraviolet ray from an ultraviolet irradiator,to prepare a sample for rubber hardness measurement, and this samplewhen measured for its rubber hardness indicated a rubber hardness of 75.

From the results in Reference Example 1, it can be seen that when thelow-molecular-weight crosslinking agent is used and compounded in a toolarge amount, the resulting sheet becomes rigid and tends to decreaseimpact resistance. That is, the amount of the low-molecular-region ispreferably 10% by weight or less.

Example 11 Preparation of Optical Resin Composition to Preparation ofTransparent Sheet

(1) The optical resin composition in Example 1 was poured into a frameof 100 mm in width, 100 mm in length and 1.0 mm in depth, and the resincomposition in a state covered at an upper part with an ultraviolettransmitting glass was irradiated with 2,000 mJ ultraviolet ray from anultraviolet irradiator to yield a transparent sheet. Then, this sheetwas stuck to a float glass of 2.8 mm in thickness for shield glass,further stuck to a glass of 0.7 mm in thickness, and subjected to animpact resistance test in the same manner as in Example 1. As a result,the shield glass was not broken at 0.25 J but broken at 0.4 J. From thisresult, it is estimated that this sheet is practically not problematic,but the sheet when compared with those in the other examples tends todeteriorate impact resistance when the thickness of the transparentsheet is too thick.

Comparative Example 1

When only the glass of 0.7 mm in thickness was examined for impactresistance in the same manner as in Example 1, the glass was broken at0.25 J.

Example 12 Preparation of Acrylate Derivative Polymer

In a reaction container equipped with a condenser, a thermometer, astirrer, a dropping funnel and a nitrogen inlet tube, 84.0 g of2-ethylhexyl acrylate (AA monomer), 36.0 g of 2-hydroxyethyl acrylate(HA monomer) and 150.0 g of methyl isobutyl ketone were heated asinitial monomers from ordinary temperature to 70° C. over 15 minutes,while the atmosphere in the reaction container was replaced withnitrogen at a gas flow rate of 100 ml/min. To this solution kept at thistemperature was dropped a solution prepared by dissolving 0.6 g oflauroyl peroxide in 21.0 g of 2-ethylhexyl acrylate and 9.0 g of2-hydroxyethyl acrylate as additional monomers over 60 minutes. Aftercompletion of dropping, the mixture was further reacted for 2 hours.Subsequently, a 2-ethylhexyl acrylate/2-hydroxyethyl acrylate copolymer(weight-average molecular weight of 250,000) was obtained by distillingaway the methyl isobutyl ketone.

(Preparation of Optical Resin Composition to Preparation of TransparentSheet)

The above copolymer 44.50 g 2-Ethylhexyl acrylate (AA monomer) 38.25 g2-Hydroxyethyl acrylate (HA monomer) 16.25 g 1,6-Hexanediol diacrylate 1.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone  0.50 g (photopolymerizationinitiator)

The above components were stirred and mixed to prepare (6) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. The curing shrinkage of thisresin composition was 5.5%, and the sheet had a total lighttransmittance of 92%, a birefringence of 0.5 nm, and a storage elasticmodulus of 1.8×10⁵ at 25° C. Then, this sheet was stuck to a float glassof 2.8 mm in thickness for shield glass, further stuck to a glass of 0.7mm in thickness, and subjected to an impact resistance test in the samemanner as in Example 1. As a result, the shield glass was not broken at0.6 J but broken at 0.75 J.

The resin composition was poured into a frame of 40 mm in width, 40 mmin length and 10 mm in depth, and the composition in a state covered atan upper part with an ultraviolet transmitting glass was irradiated with9,000 mJ ultraviolet ray from an ultraviolet irradiator, to prepare asample for rubber hardness measurement, and this sample when measuredfor its rubber hardness indicated a rubber hardness of 2.

Example 13

The copolymer in Example 12 42.75 g 2-Ethylhexyl acrylate (AA monomer)36.58 g 2-Hydroxyethyl acrylate (HA monomer) 15.67 g 1,6-Hexanedioldiacrylate  5.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone  0.50 g(photopolymerization initiator)

The above components were stirred and mixed to prepare (7) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet (optical resin material). Thecuring shrinkage of this resin composition was 5.7%, and the sheet had atotal light transmittance of 92% and a birefringence of 0.6 nm. Then,this sheet was stuck to a float glass of 2.8 mm in thickness for shieldglass, further stuck to a glass of 0.7 mm in thickness, and subjected toan impact resistance test in the same manner as in Example 1. As aresult, the shield glass was not broken at 1.0 J but broken at 1.25 J.

The resin composition was poured into a frame of 40 mm in width, 40 mmin length and 10 mm in depth, and the composition in a state covered atan upper part with an ultraviolet transmitting glass was irradiated with9,000 mJ ultraviolet ray from an ultraviolet irradiator to prepare asample for rubber hardness measurement, and this sample when measuredfor its rubber hardness indicated a rubber hardness of 22.

Example 14

The copolymer in Example 12  40.5 g 2-Ethylhexyl acrylate (AA monomer)34.65 g 2-Hydroxyethyl acrylate (HA monomer) 14.85 g 1,6-Hexanedioldiacrylate 10.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone  0.50 g(photopolymerization initiator)

The above components were stirred and mixed to prepare (8) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet (optical resin material). Thecuring shrinkage of this resin composition was 6.1% and the total lighttransmittance of the sheet was 91%. Then, this sheet was stuck to afloat glass of 2.8 mm in thickness for shield glass, further stuck to aglass of 0.7 mm in thickness, and subjected to an impact resistance testin the same manner as in Example 1. As a result, the shield glass wasnot broken at 0.5 J but broken at 0.75 J.

The resin composition was poured into a frame of 40 mm in width, 40 mmin length and 10 mm in depth, and the composition in a state covered atan upper part with an ultraviolet transmitting glass was irradiated with9,000 mJ ultraviolet ray from an ultraviolet irradiator to prepare asample for rubber hardness measurement, and this sample when measuredfor its rubber hardness indicated a rubber hardness of 38.

Example 15

(6) The optical resin composition in Example 12 was poured into a frameof 100 mm in width, 100 mm in length and 0.15 mm in depth, and the resincomposition in a state covered at an upper part with an ultraviolettransmitting glass was irradiated with 2,000 mJ ultraviolet ray from anultraviolet irradiator to yield a transparent sheet. Then, this sheetwas stuck to a float glass of 2.8 mm in thickness for shield glass,further stuck to a glass of 0.7 mm in thickness, and subjected to animpact resistance test in the same manner as in Example 1. As a result,the shield glass was not broken at 0.75 J but broken at 1.0 J.

Example 16

A sheet prepared in the same manner as in Example 12 was stuck to afloat glass of 6.0 mm in thickness for shield glass, further stuck to aglass of 0.7 mm in thickness, and subjected to an impact resistance testin the same manner as in Example 1. As a result, the shield glass wasnot broken at 2.75 J but broken at 3.0 J.

Example 17

A sheet prepared in the same manner as in Example 12 was stuck to afloat glass of 1.3 mm in thickness for shield glass, further stuck to aglass of 0.7 mm in thickness, and subjected to an impact resistance testin the same manner as in Example 1. As a result, the shield glass wasnot broken at 0.4 J but broken at 0.5 J.

Example 18

A strip of 0.5 mm in thickness and 5 mm in width was stuck as a frame toall sides of an AG-treated polarization plate stuck to the surface of aliquid crystal display cell of 32 inches in diagonal length. (6) Thesame optical resin composition as in Example 12 was poured into theframe, and then its surface was covered so as not to contain bubbleswith a soda glass of 32 inches in diagonal length and 2.8 mm inthickness on which an antireflective layer had been formed. Then, theresin was cured by irradiation with an integrated exposure of 2,000 mJultraviolet ray from a conveyor ultraviolet irradiator using a metalhalide lamp, thereby giving a liquid crystal display cell having anoptical resin material and a transparent protective substrate. Thisliquid crystal display cell was set in a body having a backlight unitand a driving circuit to produce a liquid crystal display (image displaydevice).

This liquid crystal display was free of color change resulting fromcoloring of the resin material therein and did not show releasing orfloating, in the interface, of a liquid crystal display shock absorberor the transparent protective substrate. There was no imagedeterioration due to ghost image, and upon touching the surface, therewas no image deterioration attributable to sagging of the panel.

Example 19

The same transparent sheet as obtained in Example 12 was obtained. Thissheet was transparent even after a moisture absorption test. Then, thissheet was stuck to an electromagnetic shielding layer of anelectromagnetic shielding film U (TT42-01) A manufactured by HitachiChemical Co., Ltd. to prepare an optical filter having electromagneticshielding property. When this filter was measured in the followingimpact resistance test, the glass was not broken with an impact of 1.1 Jbut broken with an impact of 1.2 J. Breakage of the resin sheet was notobserved.

—Impact Resistance Test—

In the impact resistance test, the resin sheet stuck to theelectromagnetic shielding film was further stuck to a soda glass of 2.8mm in thickness, and a steel ball was dropped onto it to evaluate impactresistance. The impact was increased by 0.1 J increments, and thestrength of impact just before the glass or the resin sheet had beenbroken was regarded as impact resistance.

Example 20

The copolymer in Example 12 19.75 g 2-Ethylhexyl acrylate (AA monomer)55.50 g 2-Hydroxyethyl acrylate (HA monomer) 23.75 g 1,6-Hexanedioldiacrylate  1.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone(photopolymerization  0.50 g initiator)

A transparent sheet (optical resin material) was prepared in the samemanner as in Example 12 except that the above components were used toprepare (9) an optical resin composition. This sheet was transparent andmaintained transparency even after a moisture absorption test. Thecuring shrinkage of this resin composition was 9.6% and the total lighttransmittance of the sheet was 92%. Then, this sheet was stuck to anelectromagnetic shielding layer of an electromagnetic shielding film U(TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected toan impact resistance test in the same manner as in Example 19. As aresult, the glass was not broken with an impact of 1.1 J but broken withan impact of 1.2 J. Breakage of the resin sheet was not observed.

Example 21

The copolymer in Example 12 54.50 g 2-Ethylhexyl acrylate (AA monomer)31.25 g 2-Hydroxyethyl acrylate (HA monomer) 13.25 g 1,6-Hexanedioldiacrylate  1.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone(photopolymerization  0.50 g initiator)

A transparent sheet (optical resin material) was prepared in the samemanner as in Example 12 except that the above components were used toprepare (10) an optical resin composition. This sheet was transparentand maintained transparency even after a moisture absorption test. Thecuring shrinkage of this resin composition was 5.0% and the total lighttransmittance of the sheet was 92%. Then, this sheet was stuck to anelectromagnetic shielding layer of an electromagnetic shielding film U(TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected toan impact resistance test in the same manner as in Example 19. As aresult, the glass was not broken with an impact of 1.1 J but broken withan impact of 1.2 J. Breakage of the resin sheet was not observed.

Example 22 Synthesis of Acrylate Derivative Polymer

A 2-ethylhexyl acrylate/2-hydroxyethyl acrylate copolymer(weight-average molecular weight of 200,000) was obtained in the samemanner as in Example 1 except that 102.0 g of 2-ethylhexyl acrylate (AAmonomer) and 18.0 g of 2-hydroxyethyl acrylate (HA monomer) were used asinitial monomers and 25.5 g of 2-ethylhexyl acrylate and 4.5 g of2-hydroxyethyl acrylate were used as additional monomers.

(Preparation of Optical Resin Composition to Preparation of TransparentSheet)

The above copolymer 44.50 g  2-Ethylhexyl acrylate (AA monomer) 46.25 g 2-Hydroxyethyl acrylate (HA monomer) 8.25 g 1,6-Hexanediol diacrylate1.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone (photopolymerization 0.50 ginitiator)

A transparent sheet (optical resin material) was prepared in the samemanner as in Example 12 except that the above components were used toprepare (11) an optical resin composition. This sheet was transparentand maintained transparency even after a moisture absorption test. Thecuring shrinkage of this resin composition was 5.4% and the total lighttransmittance of the sheet was 92%. Then, this sheet was stuck to anelectromagnetic shielding layer of an electromagnetic shielding film U(TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected toan impact resistance test in the same manner as in Example 19. As aresult, the glass was not broken with an impact of 1.3 J but broken withan impact of 1.4 J. Breakage of the resin sheet was not observed.

Example 23 Synthesis of Acrylate Derivative Polymer

A 2-ethylhexyl acrylate/2-hydroxyethyl acrylate copolymer(weight-average molecular weight of 350,000) was obtained in the samemanner as in Example 1 except that 60.0 g of 2-ethylhexyl acrylate (AAmonomer) and 60.0 g of 2-hydroxyethyl acrylate (HA monomer) were used asinitial monomers and 15.0 g of 2-ethylhexyl acrylate and 15.0 g of2-hydroxyethyl acrylate were used as additional monomers.

(Preparation of Optical Resin Composition to Preparation of TransparentSheet)

The above copolymer 44.50 g 2-Ethylhexyl acrylate (AA monomer) 27.25 g2-Hydroxyethyl acrylate (HA monomer) 27.25 g 1,6-Hexanediol diacrylate 1.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone (photopolymerization  0.50 ginitiator)

A transparent sheet (optical resin material) was prepared in the samemanner as in Example 12 except that the above components were used toprepare an optical resin composition (12). This sheet was transparentand maintained transparency even after a moisture absorption test. Then,this sheet was stuck to an electromagnetic shielding layer of anelectromagnetic shielding film U (TT42-01) A manufactured by HitachiChemical Co., Ltd. and subjected to an impact resistance test in thesame manner as in Example 19. As a result, the glass was not broken withan impact of 1.1 J but broken with an impact of 1.2 J. Breakage of theresin sheet was not observed.

Example 24

A transparent sheet (optical resin material) was prepared in the samemanner as in Example 12 except that an optical resin composition (6)′using bis(2,4,6-trimethyl benzoyl)-phenylphosphine oxide was used as thephotopolymerization initiator in place of1-hydroxy-cyclohexyl-phenyl-ketone, a frame of 100 mm in width, 100 mmin length and 3.0 mm in depth was used, and the exposure amount ofultraviolet ray was 4,500 mJ. This sheet was transparent and maintainedtransparency even after a moisture absorption test. Then, this sheet wasstuck to an electromagnetic shielding layer of an electromagneticshielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd.and subjected to an impact resistance test in the same manner as inExample 19. As a result, the glass was not broken even with an impact of2.0 J. Breakage of the resin sheet was not observed.

Example 25

A transparent sheet (optical resin material) was prepared in the samemanner as in Example 12 except that (6)″ an optical resin compositionusing 2.00 g ofoligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone was usedas the photopolymerization initiator in place of1-hydroxy-cyclohexyl-phenyl-ketone, and the exposure amount ofultraviolet ray was 2,500 mJ. This sheet was transparent and maintainedtransparency even after a moisture absorption test. Particularly, theodor of this sheet was reduced. Then, this sheet was stuck to anelectromagnetic shielding layer of an electromagnetic shielding film U(TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected toan impact resistance test in the same manner as in Example 19. As aresult, the glass was not broken with an impact of 1.1 J but broken withan impact of 1.2 J. Breakage of the resin sheet was not observed.

Example 26

A transparent sheet (optical resin material) was prepared in the samemanner as in Example 12 except that a frame of 100 mm in width, 100 mmin length and 1.5 mm in depth was used and the exposure amount ofultraviolet ray was 3,500 mJ. This sheet was transparent and maintainedtransparency even after a moisture absorption test. Then, this sheet wasstuck to an electromagnetic shielding layer of an electromagneticshielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd.and subjected to an impact resistance test in the same manner as inExample 19. As a result, the glass was not broken even with an impact of2.0 J. Breakage of the resin sheet was not observed.

Example 27

A transparent sheet (optical resin material) was prepared in the samemanner as in Example 12 except that a frame of 100 mm in width, 100 mmin length and 2.0 mm in depth was used and the exposure amount ofultraviolet ray was 4,000 mJ. This sheet was transparent and maintainedtransparency even after a moisture absorption test. Then, this sheet wasstuck to an electromagnetic shielding layer of an electromagneticshielding film U (TT42-01) A manufactured by Hitachi Chemical Co., Ltd.and subjected to an impact resistance test in the same manner as inExample 19. As a result, the glass was not broken even with an impact of2.0 J. Breakage of the resin sheet was not observed.

Example 28

The copolymer in Example 12 40.20 g 2-Ethylhexyl acrylate (AA monomer)44.10 g 2-Hydroxyethyl acrylate (HA monomer) 14.70 g 1,6-Hexanedioldiacrylate  1.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone(photopolymerization  0.50 g initiator)

A transparent sheet (optical resin material) was prepared in the samemanner as in Example 12 except that the above components were used toprepare (13) an optical resin composition. This sheet was transparentand maintained transparency even after a moisture absorption test. Then,this sheet was stuck to an electromagnetic shielding layer of anelectromagnetic shielding film U (TT42-01) A manufactured by HitachiChemical Co., Ltd. and subjected to an impact resistance test in thesame manner as in Example 19. As a result, the glass was not broken withan impact of 1.1 J but broken with an impact of 1.2 J. Breakage of theresin sheet was not observed.

Reference Example 2

The copolymer in Example 12 44.50 g 2-Ethylhexyl acrylate 54.50 g2-Hydroxyethyl acrylate 13.25 g 1,6-Hexanediol diacrylate  1.00 g1-Hydroxy-cyclohexyl-phenyl-ketone  0.50 g

A sheet was prepared in the same manner as in Example 12 except that theabove components were used to prepare (14) an optical resin composition.The resulting sheet had been clouded.

Reference Example 3

The copolymer in Example 12 44.50 g 2-Ethylhexyl acrylate 54.50 g1,6-Hexanediol diacrylate  1.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone 0.50 g

A sheet was prepared in the same manner as in Example 12 except that theabove components were used to prepare (15) an optical resin composition.The resulting sheet had been clouded.

From the results in Reference Examples 2 and 3, it can be seen that thetransparency of the sheet just after production is decreased as thedifference in numerical value between P and M in the formula (I)increases.

Reference Example 4

A copolymer (weight-average molecular weight of 220,000) was obtained inthe same manner as in Example 12 except that 108.0 g of 2-ethylhexylacrylate and 12.0 g of 2-hydroxyethyl acrylate were used as initialmonomers and 27.0 g of 2-ethylhexyl acrylate and 3.0 g of 2-hydroxyethylacrylate were used as additional monomers.

The copolymer above 49.50 g  2-Ethylhexyl acrylate 44.50 g 2-Hydroxyethyl acrylate 5.00 g 1,6-Hexanediol diacrylate 1.00 g1-Hydroxy-cyclohexyl-phenyl-ketone 0.50 g

A sheet was prepared in the same manner as in Example 12 except that theabove components were used to prepare (16) an optical resin composition.The resulting sheet was transparent but became clouded after a moistureabsorption test.

Reference Example 5 Preparation of Acrylate Derivative Polymer

A copolymer was obtained in the same manner as in Example 12 except that12.0 g of 2-ethylhexyl acrylate (AA monomer) and 108.0 g of2-hydroxyethyl acrylate (HA monomer) were used as initial monomers and3.0 g of 2-ethylhexyl acrylate and 27.0 g of 2-hydroxyethyl acrylatewere used as additional monomers.

(Preparation of Optical Resin Composition to Preparation of TransparentSheet)

The copolymer above 49.50 g  2-Ethylhexyl acrylate 5.00 g 2-Hydroxyethylacrylate 44.50 g  1,6-Hexanediol diacrylate 1.00 g1-Hydroxy-cyclohexyl-phenyl-ketone 0.50 g

A sheet was prepared in the same manner as in Example 12 except that theabove components were used to prepare (17) an optical resin composition.The resulting sheet was transparent, but after a moisture absorptiontest, its outside dimension was increased by 5% or more to generateswelling in the periphery thereof.

From the results in Reference Examples 4 and 5, it is estimated thatwhen the balance between AA monomer and HA monomer is bad, the productmay become clouded or undergo a significant dimensional change. However,even in such case, it is considered that there is no problem as long asthe product is used in a hermetically sealed site where it hardlyabsorbs moisture.

Comparative Example 2 Preparation of Optical Resin Composition toPreparation of Transparent Sheet

2-Ethylhexyl acrylate 84.15 g 2-Hydroxyethyl acrylate 14.85 g1,6-Hexanediol diacrylate  1.00 g 1-Hydroxy-cyclohexyl-phenyl-ketone 0.50 g

A sheet was prepared in the same manner as in Example 12 except that theabove components were used to prepare an optical resin composition (18).This sheet was transparent and maintained transparency even after amoisture absorption test. Then, this sheet was stuck to anelectromagnetic shielding layer of an electromagnetic shielding film U(TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected toan impact resistance test in the same manner as in Example 19. As aresult, the resin sheet was broken with an impact of 0.5 J.

Comparative Example 3

An electromagnetic shielding film U (TT42-01) A was stuck directly onglass such that its electromagnetic shielding layer was contacted withthe glass, and then examined for its impact resistance in the samemanner as in Example 19. As a result, the glass was broken with animpact of 0.5 J.

Example 29

The copolymer in Example 12 10.00 g 2-Ethylhexyl acrylate 62.30 g2-Hydroxyethyl acrylate 26.70 g 1,6-Hexanediol diacrylate  1.00 g1-Hydroxy-cyclohexyl-phenyl-ketone  0.50 g

A sheet was prepared in the same manner as in Example 12 except that theabove components were used to prepare an optical resin composition (19).The resulting sheet was transparent and maintained transparency evenafter a moisture absorption test. Then, this sheet was stuck to anelectromagnetic shielding layer of an electromagnetic shielding film U(TT42-01) A manufactured by Hitachi Chemical Co., Ltd. and subjected toan impact resistance test in the same manner as in Example 19. As aresult, the glass was not broken with an impact of 0.7 J but broken withan impact of 0.8 J.

Example 30

A transparent sheet was obtained in the same manner as in Example 1except that 0.40 g of lauryl peroxide was used in place of 0.50 g of1-hydroxy-cyclohexyl-phenyl-ketone in Example 1 to prepare (1) anoptical resin composition’ and also that heating for 3 hours in a fanoven at 70° C. was conducted in place of irradiation with ultravioletray ((1)′ the optical resin composition was poured into a frame andheated in a state covered at an upper part with an ultraviolettransmitting glass). This sheet showed high impact resistance similar tothat of the sheet in Example 1, and did not show white turbidity uponmoisture absorption.

Example 31

A transparent sheet was obtained in the same manner as in Example 3except that 0.10 g of t-hexylperoxy pivalate was further added to theresin composition in Example 3 to prepare (3)′ an optical resincomposition and the sheet was irradiated with ultraviolet ray and thenfurther heated at 70° C. for 1 hour in a nitrogen oven (the opticalresin composition was poured into a frame and heated in a state coveredat an upper part with an ultraviolet transmitting glass). Thistransparent sheet did not show deterioration in characteristics byaddition of the thermopolymerization initiator or by heating, and showedhigh impact resistance and transparency upon moisture absorption,similar to those of the transparent sheet in Example 3.

Example 32

A transparent sheet was obtained in the same manner as in Example 4except that 0.20 g of 2,2′-azobisisobutyronitrile was used in place of0.50 g of 1-hydroxy-cyclohexyl-phenyl-ketone in Example 4 to prepare(4)′ an optical resin composition, and also that heating for 3 hours ina fan oven at 70° C. was conducted in place of irradiation withultraviolet ray (the optical resin composition was poured into a frameand heated in a state covered at an upper part with an ultraviolettransmitting glass). This transparent sheet showed high impactresistance similar to that of the transparent sheet in Example 1, anddid not show white turbidity upon moisture absorption.

Example 33

A transparent sheet was obtained in the same manner as in Example 4except that 0.05 g of 2,2′-azobis(2,4-dimethylvaleronitrile) was furtheradded to the optical resin composition in Example 4 to prepare (4)″ anoptical resin composition and the sheet was irradiated with 300 mJultraviolet ray and then further heated at 70° C. for 1 hour in anitrogen oven (the optical resin composition was poured into a frame andheated in a state covered at an upper part with an ultraviolettransmitting glass). This transparent sheet did not show deteriorationin characteristics by addition of the thermopolymerization initiator orby heating, and showed high impact resistance and transparency uponmoisture absorption, similar to those of the transparent sheet inExample 4.

Example 34

A frame was prepared in the same manner as in Example 7, (3)′ the sameoptical resin composition as in Example 31 was poured into the frame andthen covered with the same glass as in Example 7. Then, the sample washeated at 70° C. for 1 hour with a fan oven, thereby curing the resin toproduce a liquid crystal display cell having an optical resin materialand a transparent protective substrate. This liquid crystal display cellwas set in a body having a backlight unit or a driving circuit toproduce a liquid crystal display (image display device). This liquidcrystal display was free of color change resulting from coloring of theresin material therein and did not show releasing or floating, in theinterface, of the optical resin material or the transparent protectivesubstrate, similarly to Example 7. There was no image deterioration dueto ghost image, and upon touching the surface, there was nodeterioration in image quality by sagging of the panel.

Example 35

A frame was prepared in the same manner as in Example 7, (1)′ the sameoptical resin composition as in Example 30 was poured into the frame andthen covered without bubbles on the surface with an acrylic plate of 3mm in thickness. Then, the sample was heated at 70° C. for 1 hour with afan oven, thereby curing the resin to produce a liquid crystal displaycell having an optical resin material and a transparent protectivesubstrate. This liquid crystal display cell was set in a body having abacklight unit or a driving circuit to produce a liquid crystal display(image display device). This liquid crystal display was free of colorchange resulting from coloring of the resin material therein and did notshow releasing or floating, in the interface, of the optical resinmaterial or the transparent protective substrate, similarly to Examples1 or 7. There was no image deterioration due to ghost image, and upontouching the surface, there was no deterioration in image quality bysagging of the panel.

Example 36

A sheet prepared in the same manner as in Example 30 was stuck to theelectromagnetic shielding layer side of a substrate film in anelectromagnetic shielding film U (TT42-01) A manufactured by HitachiChemical Co., Ltd. to prepare an optical filter having electromagneticshielding property. When this filter was subjected to an impactresistance test, the glass was not broken with an impact of 0.8 J butbroken with an impact of 0.9 J, similarly to Example 8. Breakage of theresin sheet was not observed.

Example 37

The resin composition in Example 33 was applied onto a polyester film,then covered with a cover film, irradiated with 300 mJ ultraviolet raythereby eliminating the fluidity of the resin, and cured for 1 hour in ahardening furnace at 70° C. to produce a sheet of 42-inch size. Thissheet was stuck by a roller laminator on a transparent resin layer of anelectromagnetic shielding film U (TT42-01) A manufactured by HitachiChemical Co., Ltd. to produce an electromagnetic shielding film with animpact-absorbing layer. The substrate polyester film side of theelectromagnetic shielding film was further stuck by a roller laminatoron an antireflective film having an infrared shielding function or avisible light wavelength selection absorption function (Clearlas NIR-SA,manufactured by SUMITOMO OSAKA CEMENT Co., Ltd.) to manufacture adirectly stuck filter for plasma display (optical filter). This directlystuck filter was stuck by a laminator to a plasma display panel via theadhesion of the impact-absorbing layer, and when an image was displayed,a display excellent in contrast without a ghost image was obtainedsimilarly to Example 10.

Example 38

The copolymer in Example 1 24.88 g 2-Ethylhexyl acrylate (AA monomer)28.65 g 2-Hydroxyethyl acrylate (HA monomer) 11.14 g Polyurethaneacrylate in Example 1 34.83 g 1-Hydroxy-cyclohexyl-phenyl-ketone(photopolymerization  0.50 g initiator)

The above components were stirred and mixed to prepare (20) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. Then, this sheet was stuck to afloat glass of 2.8 mm in thickness for shield glass, further stuck to aglass of 0.7 mm in thickness, and subjected to an impact resistance testin the same manner as in Example 1. As a result, the shield glass wasnot broken at 0.6 J but broken at 0.75 J. This sheet maintainedtransparency even after a moisture absorption test.

Example 39

The copolymer in Example 1 24.88 g 2-Ethylhexyl acrylate (AA monomer)25.86 g 2-Hydroxyethyl acrylate (HA monomer) 13.93 g Polyurethaneacrylate in Example 1 34.83 g 1-Hydroxy-cyclohexyl-phenyl-ketone(photopolymerization  0.50 g initiator)

The above components were stirred and mixed to prepare (21) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. Then, this sheet was stuck to afloat glass of 2.8 mm in thickness for shield glass, further stuck to aglass of 0.7 mm in thickness, and subjected to an impact resistance testin the same manner as in Example 1. As a result, the shield glass wasnot broken at 0.6 J but broken at 0.75 J. This sheet maintainedtransparency even after a moisture absorption test.

Example 40

The copolymer in Example 1 24.88 g 2-Ethylhexyl acrylate (AA monomer)31.04 g 2-Hydroxyethyl acrylate (HA monomer)  8.75 g Polyurethaneacrylate in Example 1 34.83 g 1-Hydroxy-cyclohexyl-phenyl-ketone(photopolymerization  0.50 g initiator)

The above components were stirred and mixed to prepare (22) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. Then, this sheet was stuck to afloat glass of 2.8 mm in thickness for shield glass, further stuck to aglass of 0.7 mm in thickness, and subjected to an impact resistance testin the same manner as in Example 1. As a result, the shield glass wasnot broken at 0.6 J but broken at 0.75 J. This sheet was observed to beturbid just after production, but became transparent after a moistureabsorption test.

Example 41

The copolymer in Example 1 24.88 g 2-Ethylhexyl acrylate (AA monomer)34.55 g 2-Hydroxyethyl acrylate (HA monomer)  5.24 g Polyurethaneacrylate in Example 1 34.83 g 1-Hydroxy-cyclohexyl-phenyl-ketone(photopolymerization  0.50 g initiator)

The above components were stirred and mixed to prepare (23) an opticalresin composition which was then poured into a frame of 100 mm in width,100 mm in length and 0.5 mm in depth, and the resin composition in astate covered at an upper part with an ultraviolet transmitting glasswas irradiated with 2,000 mJ ultraviolet ray from an ultravioletirradiator to yield a transparent sheet. Then, this sheet was stuck to afloat glass of 2.8 mm in thickness for shield glass, further stuck to aglass of 0.7 mm in thickness, and subjected to an impact resistance testin the same manner as in Example 1. As a result, the shield glass wasnot broken at 0.6 J but broken at 0.75 J. This sheet was slightly turbidjust after production and maintained turbidity after a moistureabsorption test.

From the results in Examples 40 and 41, it can be seen that as thedifference in numerical value between P and M in the formula (I) isincreased, the transparency of the sheet just after production isdecreased. However, the degree of turbidity was lower compared from thecase of the high-molecular-weight crosslinking agent than thelow-molecular-weight, and thus the high-molecular-weight crosslinkingagent may be used depending on its grade or the thickness of a sheet.

Example 42

(1) The optical resin composition in Example 1 was poured into a frameof 100 mm in width, 100 mm in length and 0.15 mm in depth, and the resincomposition in a state covered at an upper part with an ultraviolettransmitting glass was irradiated with 2,000 mJ ultraviolet ray from anultraviolet irradiator to yield a transparent sheet. Then, this sheetwas stuck to a float glass of 2.8 mm in thickness for shield glass,further stuck to a glass of 0.7 mm in thickness, and subjected to animpact resistance test in the same manner as in Example 1. As a result,the shield glass was neither broken at 0.75 J nor broken even at 1.0 J.

The test methods in the Examples, Comparative Examples and ReferenceExamples are shown below. The results in these tests are shown in Tables1 to 6.

In Tables 1 to 6, *1 to *4 are the following treatments conducted beforethe impact resistance test in the Examples and Comparative Examples,respectively.

*1: A sheet was stuck to a float glass of 2.8 mm in thickness for shieldglass and further stuck to a glass of 0.7 mm in thickness, followed bybeing subjected to the impact resistance test.

*2: A sheet was stuck to a float glass of 6.0 mm in thickness for shieldglass and further stuck to a glass of 0.7 mm in thickness, followed bybeing subjected to the impact resistance test.

*3: A sheet was stuck to a float glass of 1.3 mm in thickness for shieldglass and further stuck to a glass of 0.7 mm in thickness, followed bybeing subjected to the impact resistance test.

*4: A sheet was stuck to the electromagnetic shielding layer side of asubstrate film in the electromagnetic shielding film to prepare anoptical filter having electromagnetic shielding property, followed bybeing subjected to the impact resistance test.

(Measurement of Weight-Average Molecular Weight)

Weight-average molecular weight was measured by gel permeationchromatography with THF as solvent and determined using a calibrationcurve of standard polystyrenes.

(Measurement of Rubber Hardness)

A sample of 40 mm in width, 40 mm in length and 10 mm in width was usedand measured for its rubber hardness with a spring-type hardness meter(WR-104A) manufactured by Nishi Tokyo Seiki Co., Ltd. The measurementwas carried out at 5 positions, and an average value at the 5 positionswas indicated as rubber hardness.

(Curing Shrinkage)

From the density of a ultraviolet curable liquid measured with apicnometer and the density of its ultraviolet cured product measuredwith an electronic density meter SD-200L (manufactured by ALFA MIRAGECo., LTd.), curing shrinkage was calculated using the followingequation.Curing shrinkage=(density of ultraviolet cured product-density ofultraviolet curable liquid)/density of ultraviolet cured product×100(Birefringence)

A ultraviolet cured product was cut in a size of 40×40 mm and measuredfor its phase contrast with Ellipsometer AEP-100 (manufactured byShimadzu Corporation), and the measured phase contrast was indicated asbirefringence.

(Moisture Absorption Test)

In the moisture absorption test, a resin sheet was placed in a hightemperature/high humidity chamber at 60° C. and 90% RH for 50 hours andthe evaluation method was by visual observation. After the test, itstotal light transmittance was measured.

(Transparency)

A prepared sheet was evaluated for its transparency under the followingevaluation criteria visually.

—Evaluation Criteria—

A: Recognized to be colorless and transparent.

B: Slightly turbid, but at a level practically unproblematic dependingon grade or the thickness of the sheet.

C: Apparently turbid and at an unusable level.

(Elastic Modulus)

A ultraviolet cured product was cut in a size of 3 mm in width and 20 mmin length and measured by a stretching method at a measuring frequencyof 1 Hz with RSA-III manufactured by TA Instruments.

(Total Light Transmittance)

Total light transmittance was measured with a color difference/turbiditymeasuring instrument COH-300A (manufactured by Nippon DenshokuIndustries Co., Ltd.).

TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6Example 7 Example 8 Example 9 Resin (A) Acrylate derivative 39.79 g45.54 g 39.20 g 47.50 g 39.79 g 39.79 g 39.79 g 39.79 g 45.54 gComposition AA monomer 27.85 g 31.88 g 27.44 g 33.25 g 27.85 g 27.85 g27.85 g 27.85 g 31.88 g HA monomer 11.94 g 13.66 g 11.76 g 14.25 g 11.94g 11.94 g 11.94 g 11.94 g 13.66 g (B) High-molecular- 34.83 g 13.86 g34.30 g 5.00 g 34.83 g 34.83 g 34.83 g 34.83 g 13.86 g weightcrosslinking agent (B) Low-molecular- — — — — — — — — — weightcrosslinking agent (C) Acrylate 24.88 g 39.60 g 24.50 g 47.00 g 24.88 g24.88 g 24.88 g 24.88 g 39.60 g derivative polymer AA monomer 105.0 g105.0 g 105.0 g 105.0 g 105.0 g 105.0 g 105.0 g 105.0 g 105.0 g HAmonomer  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g 45.0 g (D)  0.50 g  1.00 g  2.00 g  0.50 g  0.50 g  0.50 g  0.50 g 0.50 g  1.00 g Photopolymerization initiator (D) — — — — — — — — —Thermopolymerization initiator P (% by weight) 30 30 30 30 30 30 30 3030 M (% by weight) 30 30 30 30 30 30 30 30 30 P − M   0.0   0.0   0.0  0.0   0.0   0.0   0.0   0.0   0.0 Resin composition  (1)  (2)  (3) (4)  (1)  (1)  (1)  (1)  (2) Sheet Film thickness 0.5 mm 0.5 mm 0.5 mm0.5 mm 0.5 mm 0.5 mm — 0.5 mm 0.5 mm Evaluation Impact resistance 0.6 J*1 0.5 J *1 0.5 J *1 0.5 J *1 2.75 J *2 0.4 J *3 0.8 J *4 0.9 J *4Rubber hardness  2  0  0  1 — — — — Transparency just after A A A A — —— — production Transparency after A A A A — — — — moisture absorptiontest Device Film thickness — — — — — — 0.5 mm — — Evaluation There wasno color change, and there did not occur release etc. in an interfacewith the transparent protective substrate. A ghost image did not occur,and deterioration in image quality was not observed either. (Visibilitywas not lowered.)

TABLE 2 Reference Comparative Example 10 Example 1 Example 11 Example 1Example 12 Example 13 Example 14 Resin (A) Acrylate derivative 39.79 g38.50 g 39.79 g — 54.50 g 52.25 g 49.50 g Composition AA monomer 27.85 g26.95 g 27.85 g 38.25 g 36.58 g 34.65 g HA monomer 11.94 g 11.55 g 11.94g 16.25 g 15.67 g 14.85 g (B) High-molecular-weight 34.83 g — 34.83 g —— — crosslinking agent (B) Low-molecular-weight — 30.00 g —  1.00 g 5.00 g 10.00 g crosslinking agent (C) Acrylate derivative polymer 24.88g 31.50 g 24.88 g 44.50 g 42.75 g 40.50 g AA monomer 105.0 g 105.0 g105.0 g 105.0 g 105.0 g 105.0 g HA monomer  45.0 g  45.0 g  45.0 g  45.0g  45.0 g  45.0 g (D) Photopolymerization initiator  0.50 g  0.50 g 0.50 g  0.50 g  0.50 g  0.50 g (D) Thermopolymerization initiator — — —— — — P (% by weight) 30 30 30 30 30 30 M (% by weight) 30 30 30 30 3030 P − M   0.0   0.0   0.0 0.2   0.0   0.0 Resin composition  (1)  (5) (1)  (6)  (7)  (8) Sheet Film thickness — 0.5 mm 1.0 mm 0 mm 0.5 mm 0.5mm 0.5 mm Evaluation Impact resistance <0.25 J *1 0.25 J *1 <0.25 J *10.6 J *1 1.01 J * 0.5 J *1 Rubber hardness 75 — —  2 22 38 Transparencyjust after production A — — A A A Transparency after moisture A — — A AA absorption test Device Film thickness 0.5 mm — — — — — — EvaluationDisplay excellent in contrast without ghost image was obtained.(Visibility was improved.)

TABLE 3 Example Example Example Example Example Example Example Example15 16 17 Example 18 19 20 21 22 23 Resin (A) Acrylate derivative 54.50 g54.50 g 54.50 g 54.50 g 54.50 g 79.25 g 44.50 g 54.50 g 54.50 gComposition AA monomer 38.25 g 38.25 g 38.25 g 38.25 g 38.25 g 55.50 g31.25 g 46.25 g 27.25 g HA monomer 16.25 g 16.25 g 16.25 g 16.25 g 16.25g 23.75 g 13.25 g  8.25 g 27.25 g (B) High-molecular- — — — — — — — — —weight crosslinking agent (B) Low-molecular-  1.00 g  1.00 g  1.00 g 1.00 g  1.00 g  1.00 g  1.00 g  1.00 g  1.00 g weight crosslinkingagent (C) Acrylate 44.50 g 44.50 g 44.50 g 44.50 g 44.50 g 19.75 g 54.50g 44.50 g 44.50 g derivative polymer AA monomer 105.0 g 105.0 g 105.0 g105.0 g 105.0 g 105.0 g 105.0 g 127.5 g  75.0 g HA monomer  45.0 g  45.0g  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g  22.5 g  75.0 g (D)  0.50 g 0.50 g  0.50 g  0.50 g  0.50 g  0.50 g  0.50 g  0.50 g  0.50 gPhotopolymerization initiator (D) — — — — — — — — — Thermopolymerizationinitiator P (% by weight) 30 30 30 30 30 30 30 15 50 M (% by weight) 3030 30 30 30 30 30 15 50 P − M   0.2   0.2   0.2   0.2   0.2   0.0   0.2  −0.1   0.0 Resin composition  (6)  (6)  (6)  (6)  (6)  (9) (10) (11)(12) Sheet Film thickness 0.15 mm 0.5 mm 0.5 mm — 0.5 mm 0.5 mm 0.5 mm0.5 mm 0.5 mm Evaluation Impact resistance 0.75 J *1 2.75 J *2 0.4 J *31.1 J *4 1.1 J *4 1.1 J *4 1.3 J *4 1.1 J *4 Rubber hardness — — — — — —— — Transparency just — — — — A A A A after production Transparency — —— — A A A A after moisture absorption test Device Film thickness — — —0.5 mm — — — — — Evaluation There was no color change, and there did notoccur release etc. in an interface with the transparent protectivesubstrate. A ghost image did not occur, and deterioration in imagequality was not observed either. (Visibility was not lowered.)

TABLE 4 Example Example Example Example Example Refernce ReferenceReference Reference 24 25 26 27 28 Example 2 Example 2 Example 3 Example4 Resin (A) Acrylate derivative 54.50 g 54.50 g 54.50 g 54.50 g 58.80 g67.75 g 54.50 g 49.50 g 49.50 g Composition AA monomer 38.25 g 38.25 g38.25 g 38.25 g 44.10 g 54.50 g 54.50 g 44.50 g  5.00 g HA monomer 16.25g 16.25 g 16.25 g 16.25 g 14.70 g 13.25 g  0.00 g  5.00 g 44.50 g (B)High-molecular-weight — — — — — — — — — crosslinking agent (B)Low-molecular-weight  1.00 g  1.00 g  1.00 g  1.00 g  1.00 g  1.00 g 1.00 g  1.00 g  1.00 g crosslinking agent (C) Acrylate derivative 44.50g 44.50 g 44.50 g 44.50 g 40.20 g 44.50 g 44.50 g 49.50 g 49.50 gpolymer AA monomer 105.0 g 105.0 g 105.0 g 105.0 g 105.0 g 105.0 g 105.0g 135.0 g  15.0 g HA monomer  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g 45.0 g  45.0 g  15.0 g 135.0 g (D) Photopolymerization  0.50 g  2.00 g 0.50 g  0.50 g  0.50 g  0.50 g  0.50 g  0.50 g  0.50 g initiator (D)Thermopolymerization — — — — — — — — — initiator P (% by weight) 30 3030 30 30 30 30 10 90 M (% by weight) 30 30 30 30 25 20  0 10 90 P − M  0.2   0.2   0.2   0.2   5.0   10.4   30.0   −0.1   0.1 Resincomposition   (6)′   (6)″  (6)  (6) (13) (14) (15) (16) (17) Sheet Filmthickness 0.5 mm 0.5 mm 1.5 mm 2.0 mm 0.5 mm 0.5 mm 0.5 mm 0.5 mm 0.5 mmEvaluation Impact resistance 2.0 J *4 1.1 J *4 2.0 J *4 2.0 J *4 1.1 J*4 ≧0.5 J *4 ≧0.5 J *4 ≧0.5 J *4 ≧0.5 J *4 Rubber hardness — — — — — — —— — Transparency just after A A A A A C C A A production Transparencyafter moisture A A A A A C C C A absorption test Device Film thickness —— — — — — — — — Evaluation

TABLE 5 Com- Com- parative parative Exam- Exam- Example Example ExampleExample Example Exam- Example 2 Example 3 ple 29 ple 30 31 32 33 34 35ple 36 Resin (A) Acrylate derivative 99.00 g — 89.00 g 39.79 g 39.20 g47.50 g 47.50 g 39.20 g 39.79 g 39.79 g Composition AA monomer 84.15 g62.30 g 27.85 g 27.44 g 33.25 g 33.25 g 27.44 g 27.85 g 27.85 g HAmonomer 14.85 g 26.70 g 11.94 g 11.76 g 14.25 g 14.25 g 11.76 g 11.94 g11.94 g (B) High-molecular- — — 34.83 g 34.30 g  5.00 g  5.00 g 34.30 g34.83 g 34.83 g weight crosslinking agent (B) Low-molecular-  1.00 g 1.00 g — — — — — — — weight crosslinking agent (C) Acrylate — 10.00 g24.88 g 24.50 g 47.00 g 47.00 g 24.50 g 24.88 g 24.88 g derivativepolymer AA monomer 105.0 g 105.0 g 105.0 g 105.0 g 105.0 g 105.0 g 105.0g 105.0 g HA monomer  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g 45.0 g  45.0 g (D)  0.50 g  0.50 g —  2.00 g —  0.50 g  2.00 g — —Photopolymerization initiator (D) — —  0.40 g  0.10 g  0.20 g  0.05 g 0.10 g  0.40 g  0.40 g Thermopolymerization initiator P (% by weight) —30 30 30 30 30 30 30 30 M (% by weight) 30 30 30 30 30 30 30 30 P − M  0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0 Resin composition (18)(19)   (1)′   (3)′   (4)′   (4)″   (3)′   (1)′   (1)′ Sheet Filmthickness 0.5 mm 0 mm 0.5 mm 0.5 mm 0.5 mm 0.5 mm 0.5 mm — — 0.5 mmEvaluation Impact resistance <0.5 J *4 <0.5 J *4 0.7 J *4 0.6 J *1 0.5 J*1 0.6 J *1 0.5 J *1 0.8 J *4 Rubber hardness — — — — — — — —Transparency just A — A A A A A A moisture after production Transparencyafter A — A A A A A A absorption test Device Film thickness — — — — — —— 0.5 mm 0.5 mm — Evaluation There was no color change, and there didnot occur release etc. in an interface with the transparent protectivesubstrate. A ghost image did not occur, and deterioration in imagequality was not observed either. (Visibility was not lowered.)

TABLE 6 Example 37 Example 38 Example 39 Example 40 Example 41 Example42 Resin (A) Acrylate derivative 47.50 g 39.79 g 39.79 g 39.79 g 39.79 g39.79 g Composition AA monomer 33.25 g 28.65 g 25.86 g 31.04 g 34.55 g27.85 g HA monomer 14.25 g 11.14 g 13.93 g  8.75 g  5.24 g 11.94 g (B)High-molecular-weight  5.00 g 34.83 g 34.83 g 34.83 g 34.83 g 34.83 gcrosslinking agent (B) Low-molecular-weight — — — — — — crosslinkingagent (C) Acrylate derivative polymer 47.00 g 24.88 g 24.88 g 24.88 g24.88 g 24.88 g AA monomer 105.0 g 105.0 g 105.0 g 105.0 g 105.0 g 105.0g HA monomer  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g  45.0 g (D)Photopolymerization initiator  0.50 g  0.50 g  0.50 g  0.50 g  0.50 g 0.50 g (D) Thermopolymerization initiator  0.05 g — — — — — P (% byweight) 30 30 30 30 30 30 M (% by weight) 30 28 35 22 13 30 P − M   0.0  2.0   −5.0   8.0   16.8   0.0 Resin composition   (4)″ (20) (21) (22)(23)  (1) Sheet Film thickness — 0.5 mm 0.5 mm 0.5 mm 0.5 mm 0.15 mmEvaluation Impact resistance 0.6 J *1 0.6 J *1 0.6 J *1 0.6 J *1 1.0 J*1 Rubber hardness — — — — — Transparency just after production A A B B— Transparency after moisture A A A B — absorption test Device Filmthickness 0.5 mm — — — — — Evaluation Display excellent in contrastwithout ghost image was obtained (Visibility was improved.).

The invention claimed is:
 1. An optical resin composition for forming anoptical resin material in the shape of a sheet or film, comprising: (A)a first acrylate derivative that is a compound having one polymerizableunsaturated bond in its molecule, (B) a second acrylate derivative thatis a polyurethane di(meth)acrylate compound having two or morepolymerizable unsaturated bonds in its molecule, a diol component of thepolyurethane di(meth)acrylate compound comprising polypropylene glycolor polytetramethylene glycol, and (C) an acrylate derivative polymerthat is a copolymer obtained by polymerizing an alkyl acrylate having analkyl group containing 4 to 18 carbons with a hydroxyl-containingacrylate represented by the following general formula (I):CH₂═CHCOO(C_(m)H_(2m)O)_(n)H  General Formula (I).
 2. The optical resincomposition according to claim 1, wherein the compounding amounts of therespective components based on 100 parts by weight of (A) the firstacrylate derivative, (B) the second acrylate derivative and (C) theacrylate derivative polymer in total are (A) 14 to 89.49 parts byweight, (B) 0.1 to 50 parts by weight, and (C) 10 to 80 parts by weight.3. The optical resin composition according to claim 1, which furthercomprises (D) a polymerization initiator.
 4. The optical resincomposition according to claim 3, wherein the compounding amount of (D)the polymerization initiator based on 100 parts by weight of (A) thefirst acrylate derivative, (B) the second acrylate derivative, (C) theacrylate derivative polymer and (D) the polymerization initiator intotal is 0.01 to 5 parts by weight.
 5. The optical resin compositionaccording to claim 3, wherein (D1) a photopolymerization initiator iscontained as (D) the polymerization initiator.
 6. The optical resincomposition according to claim 5, wherein the compounding amount of (D1)the photopolymerization initiator based on 100 parts by weight of (A)the first acrylate derivative, (B) the second acrylate derivative, (C)the acrylate derivative polymer and (D1) the photopolymerizationinitiator in total is 0.1 to 5 parts by weight.
 7. The optical resincomposition according to claim 5, wherein (D1) the photopolymerizationinitiator is at least one member selected from the group consisting ofan α-hydroxyalkyl phenone compound, an acylphosphine oxide compound,oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone), and amixture of oxy-phenyl-acetic acid2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic acid2-[2-hydroxy-ethoxy]-ethyl ester.
 8. The optical resin compositionaccording to claim 1, wherein the weight-average molecular weight of (C)the acrylate derivative polymer is 100,000 to 700,000.
 9. The opticalresin composition according to claim 5, wherein the compounding amountsof the respective components based on 100 parts by weight of (A) thefirst acrylate derivative, (B) the second acrylate derivative, (C) theacrylate derivative polymer and (D1) the photopolymerization initiatorin total are (A) 15 to 40 parts by weight, (B) 5 to 40 parts by weight,(C) 39 to 59 parts by weight and (D1) 0.5 to 2.0 parts by weight.
 10. Anoptical resin material produced by curing reaction of the optical resincomposition according to claim
 1. 11. The optical resin materialaccording to claim 10, which is sheet-shaped or film-shaped.
 12. Theoptical resin material according to claim 11, wherein the sheet-shapedor film-shaped material has a thickness of 0.1 mm to 3 mm.
 13. Anoptical filter for image display device, which has a layer consisting ofan optical resin material produced by curing the optical resincomposition according to claim
 1. 14. The optical filter for imagedisplay device according to claim 13, wherein the layer has a thicknessof 0.1 mm to 3 mm.
 15. An image display device having, in a viewableside, a layer consisting of an optical resin material produced by curingthe optical resin composition according to claim
 1. 16. The imagedisplay device according to claim 15, wherein the layer has a thicknessof 0.1 mm to 3 mm.
 17. An image display device having a layer consistingof an optical resin material produced by curing the optical resincomposition according to claim 1, between an image display panel and afront panel or a transparent protective substrate.
 18. The image displaydevice according to claim 17, wherein the layer has a thickness of 0.1mm to 3 mm.
 19. The optical resin composition according to claim 1,wherein, in General Formula (I), m is 2, 3 or 4, and n is an integer of1 to
 10. 20. A method for producing an image display panel, an imagedisplay device or an optical filter, comprising: providing an opticalresin material film or sheet by curing the optical resin compositionaccording to claim 1; and laminating the optical resin material film orsheet on a surface of an image display panel or an image display deviceor on an optical filter.
 21. The method according to claim 20, whereinthe optical resin material film or sheet is laminated on the surface ofthe image display panel or the image display device or on the opticalfilter directly.
 22. The method according to claim 20, wherein theoptical resin material film or sheet is laminated on the surface of theimage display panel or the image display device or on the optical filtervia a pressure-sensitive adhesive or an adhesive.
 23. An optical resincomposition for forming an optical resin material in the shape of asheet or film, comprising: (A) a first acrylate derivative that is acompound having one polymerizable unsaturated bond in its molecule, (B)a second acrylate derivative that is a compound having two or morepolymerizable unsaturated bonds in its molecule, wherein (B) the secondacrylate derivative is a high-molecular-weight crosslinking agent havinga weight-average molecular weight of 4,000 or more and a diol componentof the second acrylate derivative comprises polypropylene glycol orpolytetramethylene glycol, and (C) an acrylate derivative polymer thatis a copolymer obtained by polymerizing an alkyl acrylate having analkyl group containing 4 to 18 carbons with a hydroxyl-containingacrylate represented by the following general formula (I):CH₂═CHCOO(C_(m)H_(2m)O)_(n)H  General Formula (I).
 24. The optical resincomposition according to claim 23, wherein the compounding amounts ofthe respective components based on 100 parts by weight of (A) the firstacrylate derivative, (B) the second acrylate derivative and (C) theacrylate derivative polymer in total are (A) 14 to 89.49 parts byweight, (B) 0.1 to 50 parts by weight, and (C) 10 to 80 parts by weight.25. The optical resin composition according to claim 23, which furthercomprises (D) a polymerization initiator.
 26. The optical resincomposition according to claim 25, wherein the compounding amount of (D)the polymerization initiator based on 100 parts by weight of (A) thefirst acrylate derivative, (B) the second acrylate derivative, (C) theacrylate derivative polymer and (D) the polymerization initiator intotal is 0.01 to 5 parts by weight.
 27. The optical resin compositionaccording to claim 25, wherein (D1) a photopolymerization initiator iscontained as (D) the polymerization initiator.
 28. The optical resincomposition according to claim 27, wherein the compounding amount of(D1) the photopolymerization initiator based on 100 parts by weight of(A) the first acrylate derivative, (B) the second acrylate derivative,(C) the acrylate derivative polymer and (D1) the photopolymerizationinitiator in total is 0.1 to 5 parts by weight.
 29. The optical resincomposition according to claim 27, wherein (D1) the photopolymerizationinitiator is at least one member selected from the group consisting ofan α-hydroxyalkyl phenone compound, an acylphosphine oxide compound,oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone), and amixture of oxy-phenyl-acetic acid2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic acid2-[2-hydroxy-ethoxy]-ethyl ester.
 30. The optical resin compositionaccording to claim 23, wherein the weight-average molecular weight of(C) the acrylate derivative polymer is 100,000 to 700,000.
 31. Theoptical resin composition according to claim 27, wherein the compoundingamounts of the respective components based on 100 parts by weight of (A)the first acrylate derivative, (B) the second acrylate derivative, (C)the acrylate derivative polymer and (D1) the photopolymerizationinitiator in total are (A) 15 to 40 parts by weight, (B) 5 to 40 partsby weight, (C) 39 to 59 parts by weight and (D1) 0.5 to 2.0 parts byweight.
 32. The optical resin composition according to claim 23, whereinthe high-molecular-weight crosslinking agent comprises a alkylene glycolcontaining 1 to 4 carbons as a part of its starting material and has aweight-average molecular weight of 4,000 to 20,000.
 33. An optical resinmaterial produced by curing reaction of the optical resin compositionaccording to claim
 23. 34. The optical resin material according to claim33, which is sheet-shaped or film-shaped.
 35. The optical resin materialaccording to claim 34, wherein the sheet-shaped or film-shaped materialhas a thickness of 0.1 mm to 3 mm.
 36. An optical filter for imagedisplay device, which has a layer consisting of an optical resinmaterial produced by curing the optical resin composition according toclaim
 23. 37. The optical filter for image display device according toclaim 36, wherein the layer has a thickness of 0.1 mm to 3 mm.
 38. Animage display device having, in a viewable side, a layer consisting ofan optical resin material produced by curing the optical resincomposition according to claim
 23. 39. The image display deviceaccording to claim 38, wherein the layer has a thickness of 0.1 mm to 3mm.
 40. An image display device having a layer consisting of an opticalresin material produced by curing the optical resin compositionaccording to claim 23, between an image display panel and a front panelor a transparent protective substrate.
 41. The image display deviceaccording to claim 40, wherein the layer has a thickness of 0.1 mm to 3mm.
 42. The optical resin composition according to claim 23, wherein thehigh-molecular-weight crosslinking agent has a weight-average molecularweight of 4,000 to 20,000.
 43. The optical resin composition accordingto claim 23, wherein, in General Formula (I), m is 2, 3 or 4, and n isan integer of 1 to
 10. 44. A method for producing an image displaypanel, an image display device or an optical filter, comprising:providing an optical resin material film or sheet by curing the opticalresin composition according to claim 23; and laminating the opticalresin material film or sheet on a surface of an image display panel oran image display device or on an optical filter.
 45. The methodaccording to claim 44, wherein the optical resin material film or sheetis laminated on the surface of the image display panel or the imagedisplay device or on the optical filter directly.
 46. The methodaccording to claim 44, wherein the optical resin material film or sheetis laminated on the surface of the image display panel or the imagedisplay device or on the optical filter via a pressure-sensitiveadhesive or an adhesive.